• Communicator 4.51 Release Notes

Last updated: March 5, 1999
[These notes are updated as we receive feedback, so please check back for new information.]

These release notes describe installation issues and known problems in Communicator 4.51. Contents include:

For an overview of the new features provided by Communicator 4.5, see the
Tour of New Features. For release notes on Mission Control Desktop tools and technology, see Mission Control Desktop 4.5.

What's New in Version 4.51

Before You Install

  • Note that Communicator 4.51 does not run on Windows 3.1 or on Macintosh 68K systems. Communicator 4.08 does run on both of these operating systems, and systems running Communicator 4.51 are fully compatible with those running the 4.08 and earlier versions.
  • On Mac OS and Windows systems with an existing version of Communicator: If you use SmartUpdate to upgrade to 4.51, be sure to click the Grant button when the Permissions dialog box appears during the installation. Clicking Grant enables the installer to continue, and you can still cancel the installation later in the process. If you click Deny, a series of Permissions dialog boxes appear, and the system sometimes quits with an error -1.
  • If you are upgrading from Navigator 2.0 or 3.0, you need to re-install any plug-ins that you want to transfer to Communicator 4.51. In order for Communicator to automatically transfer plug-ins from 4.0x versions, you must install Communicator 4.51 in the same folder as the old 4.0x version. If you install 4.51 in a different folder, you must re-install any plug-ins.
  • On Mac OS systems: If you are using a 3.0x version of Navigator and want to transfer your preferences automatically to Communicator 4.51, first upgrade to Communicator 4.08, then install Communicator 4.51.
  • On Mac OS systems: Mac OS 7.6.1 or greater is required to run Communicator 4.51. For current Apple Mac OS software, see http://support.info.apple.com. These are the recommended minimum system hardware configurations:

    • Mac OS 7.6.1: 16MB physical RAM
    • Mac OS 8.0 or greater: 24MB physical RAM
  • On Mac OS systems: Before you install Communicator, make sure that your hard disk names do not include the slash (/) character. Account Setup won't run if any of your hard disk names include the slash (/) character.

General Issues

  • On Mac OS and Windows systems: New profiles created in Communicator 4.51 aren't recognized by versions of Communicator or Navigator earlier than version 4.5.
  • If you change your user name on an IMAP server, you need to restart Communicator for the name change to take effect.
  • In Calendar on Mac OS and Windows systems: If you enter an invalid server name Calendar sometimes appears to "hang," in which case you need to restart Communicator.
  • Exported certificate names are appended with either letters or numbers. Communicator doesn't check for duplicate names, so make sure to use a unique name for each certificate.
  • Composer doesn't properly handle existing HTML files that contain CSS objects -- they may be removed from the file.

  • A zero length "cert7.db" file in the profile directory can cause Communicator to crash at startup. To avoid this, delete the zero length "cert7.db" file from the profile directory.

Roaming Access

  • On Windows systems: Clicking Cancel while uploading or downloading to an HTTP Roaming Access Server sometimes causes Communicator to quit.

  • When using a slow connection, be patient with the progress dialog boxes. Sometimes they don't immediately respond to your input during file transfers.

  • If you choose not to transfer your preferences, Communicator does not transfer your address book and IMAP mail filters, which are stored with preferences.

  • On Mac OS systems: If you enable Roaming Access, Communicator doesn't save subscribed newsgroups. To save subscribed newsgroups, go to the Edit menu and choose Preferences. Under Roaming Access, select Item, and remove the check from the Mail Filters box in the right frame.

Mail, Address Books, and Pinpoint Addressing

  • If you are upgrading from Navigator 3.0x, you need to manually import your 3.0x address book into Communicator 4.51 by opening the address book window and choosing Import under the File menu. On Mac and Windows, then select Communicator Address Book at the prompt. Enter the name of your 3.0x HTML address book file.
  • On Windows and UNIX systems: Removing ns_imap folders causes Communicator to lose the mail filters you have set up. If you suspect corrupted mail summary files, be sure to just remove the files, not entire folders or directories.
  • Communicator 4.51 allows you to create multiple address books. Pinpoint addressing searches the first 15 address books in your address book window. If you have more than 15 address books, you can select the 15 you want to use by re-ordering them in the address book window.
  • Pinpoint addressing in Communicator 4.51 searches for matches against the display name, last name, email address and nickname. Communicator 4.0x gave precedence to nickname matches. If you want exact matches against a nickname to have precedence over matches against the other fields, add this line to your javascript preferences file:

  • user_pref("ldap_2.autoComplete.nicknameHasPrecedence", true);
  • If you have an LDIF file representing an address book that was generated from Communicator 4.0x and contains 8-bit data, you can correctly import the 8-bit data into Communicator 4.51 by changing the file extension of your LDIF file to .4ld. Then, import the LDIF file like you normally would, using this new extension. You only need to do this if the file with 8-bit data was generated from a previous version of Communicator.
  • "Department," "URL," and "Prefers to receive rich text (HTML) mail" values are not exported/imported with CVS and TXT format.


  • Some HTTP proxy servers don't support Internet Keywords when the user supplies only one keyword, instead giving the error Could Not Find Host.
  • When Communicator updates a page, either through the Reload button or a meta tag, it checks for changes in HTML descriptions, but doesn't check check for changes within individual elements on the page. Because the HTML description of an image can remain the same even after the content of the image is updated, there may be applications, such as a webcam, for which you want to "force" an update.

  • To force the update of individual elements on a page, you can use meta tags:

          <META HTTP-EQUIV="Pragma" CONTENT="no-cache">
          <META HTTP-EQUIV="Refresh" CONTENT="60">

  • By default, when saving from an FTP server in Navigator, Communicator saves binary files as HTML files.


  • Previous Windows versions of Communicator had a problem sending the Accept-Language HTTP header to servers. This problem occurred if you used the Preferences command to add choices to the default language selection. This problem is corrected in Communicator 4.5 (and 4.51). If you create a new profile to use in the 4.51 release, you don't need to do anything else to remedy the problem.

  • If you are using a profile created in a previous version of Communicator, you need to overwrite the old preference settings with the correct ones. To correct the preference settings, from the Edit menu, choose Preferences. Under the Navigator category, select Languages. Either confirm that all the selections in the right pane are correct, or delete and re-enter them. Click OK.
  • When using the User Profile Manager to create a new profile, some Japanese characters that you enter in the Profile Name field of the "Choose a Name and Directory for Your Profile" dialog don't appear correctly in the directory. To correct the directory entry, delete the directory name and manually type the correct Japanese characters.

  • When copying DBCS text from Communicator to other applications under Windows NT, some characters not in the common cross-platform (Windows, Macintosh, UNIX) codepoints can become corrupted.


  • On Windows NT systems, to prevent a "system32" Windows Explorer window from appearing when Windows starts up:
  • 1) Launch the Windows Registry Editor (regedit.exe).

    2) Open this registry key: HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

    3) If the (Default) Name variable has a value of "" (an empty string), delete the Name variable.  After the deletion, the value for (Default) should be "(value not set)".

  • Messenger sometimes quits when new folders are subscribed to with SSL. This problem apparently occurs only when you automatically subscribe to all your folders on the server. To avoid it, manually choose the folders to which you wish to subscribe.
  • If you are downloading a large file and you click Cancel, Communicator may quit.
  • If you send an email message and attach a web page that contains frames, the recipient will receive the message, but with a blank attachment.
  • If you send an email message and attach a web page that contains frames, the recipient will receive the message, but with a blank attachment.

Palm-Compatible Synchronization Tools (Windows Only)

  • Back-up your Palm-compatible address book before using Address Book synchronization.
  • These are issues to be aware of when you synchronize the Palm address book with the Netscape Address Book:
    • If there are multiple lines in Palm fields (not including address and notes) Communicator converts those entries to a single line separated by commas.
    • Communicator does not automatically synchronize Palm custom fields. For more information on how to map fields between Palm and the Netscape address book fields, see the Palm Synchronization Read Me.
    • To synchronize with a directory that is synchronized offline, set Communicator to Offline.
    • To work with mail synchronization, we recommend that you send mail from Palm.

Mac OS

  • To optimize plug-in loading time, move any Read Me files that may be installed in the plug-ins folder to another folder on your hard disk.
  • When uploading a file using ftp, Communicator only sends the data fork of the file. If you want to upload a Macintosh file that has a resource fork, convert the file to BinHex or MacBinary first.
  • Folders aliases are not supported. You can drag a folder to an ftp directory window for upload but only aliases to files are resolved before they are uploaded.
  • When dragging a folder to upload, the directory hierarchy of the folder is not maintained. All files contained in the dragged folder, even those in sub-folders, are uploaded to the directory you are logged into.

  • Older versions of Norton CrashGuard are incompatible with Communicator 4.51 and may cause your system to "hang" or "quit."
  • If you are using Mac OS 8.1: You may have problems with some text files if you start Communicator using Easy Open. To avoid these problems, when the Easy Open dialog appears, do not make a selection, and cancel the dialog box. Open the Easy Open control panel. Uncheck the option "Translate 'TEXT' documents".  Close the Control Panel. You can then select your signature file.
  • If you see errors or problems while running plug-ins, Communicator may be low on memory. To provide Communicator with more memory, quit Communicator. Then, select the Netscape Communicator application icon, and choose "Get Info" from the File menu. Increase Communicator's Preferred Size by at least 1000. (If you're running Mac OS 8.5 or later, choose "Memory" from the "Show" pop-up menu to change the memory size.)
  • If you use the Real Player 5.0 Player and its plug-in software that comes with Communicator 4.51, be sure to keep the Communicator memory setting at or above the default preferred size: 8192K with virtual memory turned on. Reducing this memory setting may cause your system to quit when you use Real Player. For more information, see the Real Player site and documentation regarding recommended memory requirements.
  • If you have Adobe Type Manager installed, Communicator sometimes quits after you use the Font Preferences panel or pop-up menus on some systems.
  • Versions of Speed Doubler up to and including 1.0.1 are incompatible with Navigator and Communicator. Some disk cache operations may cause b-tree corruption on your hard drive. To correct this problem, download the latest version of Speed Doubler from the Connectix site: http://www.connectix.com

  • If you choose the "Go Offline" command and you see a dialog box that says, "The command could not be completed, because you have not set up your server preferences. Would you like to set up those preferences now?", select "OK" and enter a generic user and server name in the preference panel.

Java and JavaScript

  • JavaScript 1.3 contains an ECMA-compliant fix regarding assignments such that if (a=b) is no longer interpreted as if (a==b). You can update the code or, if you want the old behavior, specify <SCRIPT language="JavaScript1.2">.
  • If you use an applet that uses RMI callbacks, you must call netscape.security.PrivilegeManager.enablePrivilege("UniversalConnect") before your first call into the RMI runtime.


  • If you register a mime handler for 'application/x-javascript,' errors occur when you attempt to display pages that have that mimetype. For example, if you use the Navigator Applications preference to add a new mimetype for 'application/x-javascript,' then choose Save To Disk, a core dump error occurs when you display pages containing that mimetype.
  • The Linux 2.0 version of Communicator is linked against libc 5.4.22, libm 5.0.8, and XFree86 3.2.
  • The Linux 2.0 glibc version of Communicator is linked against glibc 2.0.7 and XFree86 3.3.1
  • The glibc library distributed with RedHat SparcLinux has a pagesize bug that prevents Communicator from starting. To run Communicator 4.51, you need to upgrade to the glibc-2.0.7-25 or higher RPM. This upgrade may require that you upgrade other RPMs as well.
  • If this is the very first time you've run any version of Communicator on your system, start Communicator, then exit, then start Communicator again before you use Messenger to access your mail. If you attempt to use Messenger the very first time you run Communicator, it may quit with an "Illegal instruction" message.
  • If you are using IMAP mail and would like your Sent, Templates, or Drafts folders to be located on your IMAP server, first create the folder on the server, then use Communicator Preferences to specify that you want Sent, Templates, or Drafts folders to be kept on the IMAP server.

  • To copy messages from one IMAP server to another, use the File toolbar button. You cannot drag and drop of messages from one IMAP server to another.
  • If you delete your only IMAP server and then add a POP server, Communicator may quit.
  • In the Help window:
    • The Contents window links in the left pane don't work, but those in the right pane do, and the scroll bar for the right pane also functions properly.
    • If the progress bar within the Contents window doesn't stop, you can still click the links in the right window to display topics. To stop the progress bar activity, you can close and then re-open Help.
    • The Index "look for:" field is small and it might be difficult to read, however when you type a word and press Enter, matching topics do appear. You can also scroll through the index entries.
  • If you receive Motif warnings that appear as dialog boxes, you can send those warnings to the command line instead by adding these lines to the file ~/.Xresources:
  • Netscape*useStdoutDialog:       False
    Netscape*useStderrDialog:       False
  • You should set the CLASSPATH environment variable only if you need to install special Java files in Communicator. Communicator uses CLASSPATH  to find local .class files. If CLASSPATH is set in the user's environment, only the .jar files and directories specified in the CLASSPATH are searched. If you set your CLASSPATH variable, you need to make sure that each .jar file in $MOZILLA_HOME/java/classes is listed individually in your CLASSPATH.
  • A previous workaround for Unix systems, to avoid the freezing on startup of the edit or compose window, has been changed. If you previously set editor.disable_spell_checker in the preferences.js file, you can now implement the improved fix by deleting this line from the preferences.js file:
  • user_pref("editor.disable_spell_checker", true);

    Replace it with this line:

    user_pref("editor.dont_lock_spell_files", true)

    This preference setting prevents the spell checker from locking files over NFS, thereby preventing the window freezing problem.

  • If Communicator exhibits consistent problems on pages containing Javascript, check your ~/.mailcap file, and remove this line if it is in that file:
  • application/x-javascript;;\

  • Communicator does not heed the TMPDIR environment variable when creating temporary files.

  • In order to create an IMAP container folder on servers that do not support folders containing both messages and subfolders, the folder should be created with a trailing slash, e.g., "toplevel/".
  • AIX systems: Some pages and windows may not display correctly the first time you run Communicator. Restarting Communicator corrects this problem.

  • AIX systems: Communicator 4.51 should be run using the provided "netscape" script so that the correct AIX libraries are used. If the correct libraries are not used, random problems with Communicator can occur.
  • HP-UX systems: To export security certificates:

  • 1. Enter the certificate password.
    2. In the Filter field that appears in the File dialog box, delete the "*" (asterisk) and press Enter. The File Name field at the bottom of the dialog box now shows just the directory path, without the file name.
    3. Enter the File Name and press OK to export the certificate.

Installing the Quality Feedback Agent

If you installed Communicator 4.51 for the first time, or if you removed a previous installation of Communicator 4.5 before installing Communicator 4.51, the Full Circle Talkback Quality Feedback Agent needs to be installed separately.

If you want to use the Full Circle Talkback Quality Feedback Agent to send incident reports to Netscape, you need to download it from http://home.netscape.com/download/ and follow the installation instructions provided with Talkback.

Using the Quality Feedback Agent with Automatic Proxy Configuration

If you are using automatic proxy configuration, and you want to use the Full Circle Talkback Quality Feedback Agent to send incident reports to Netscape, you need to replace the talkback.ini file with one that contains the appropriate proxy configuration information:

1.  If you are using an HTTP proxy, or both an HTTP and SOCKS proxy, create a file named talkback.ini, containing  these three lines, using your proxy host name, domain, and port:

UserHTTPProxyPort=xxxx [your proxy port number]

   If you are using a SOCKS Proxy, create a file with these three lines:

UserSOCKSPort=xxxx [your SOCKS port number]

  • 2. Replace the existing talkback.ini file with the version you created.

    On Windows 95 and Windows NT systems, copy the talkback.ini file to this location, in the directory containing Netscape.exe:


    On Mac OS systems, copy the talkback.ini file to this location in the System Folder:

    Preferences:Full Circle:Prefs:Netscape:Communicator4.51:99xxx:Talkback.ini

    ("99xxx" refers to a folder name that can vary. To find out the name of this folder for the version of Communicator that you are using, choose About Communicator from the Help menu. The actual name of the 99xxx folder appears in the title at the top of the window.)

    On Unix systems, copy the talkback.ini file in to this location:


    ("99xxx" refers to a directory name that can vary. To find out the name of this directory for the version of Communicator that you are using, choose About Communicator from the Help menu. The actual name of the 99xxx directory appears in the title at the top of the window.)

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