There are several different problems that can affect performance in OE. Many of them display very similar symptoms. If your are experiencing slow performance, begin with the problem here that best describes the symptoms you are seeing. It is possible that you have more than one issue to resolve to get OE back in top shape.
OE very slow when starting, but everything else normal
The usual cause is a missing or corrupt "Imagehlp.dll" in C:\Windows\System. Without this file, OE will be very slow to open, although usually nothing else is affected. If you uninstall a version of McAfee VirusScan and then install a later version without first restarting your computer, the McAfee install routine will delete "Imagehlp.dll" by mistake. You can either extract this file from your Win98 CDROM (using Start| Run, SFC.EXE, Extract a single file), or from your IE5/6 setup files using a command line at the setup folder like this:
extract win98_32.cab /a Imagehlp.dll
On some systems, it is found in win98_26.cab. For IE5 users on Win95/NT, it is found in setup295.cab.
Another cause of slow starts is opening OE at its home page, rather than the Inbox. Because that page is an HTML file, it is usually slower to display than is the Inbox. Click Tools| Options and place a check mark for "When starting, go directly to my Inbox folder."
On the other hand, this might also cause the problem if the Inbox is very large. The Inbox is a very active folder, and I strongly recommend that you not use it to store messages. Create subfolders and move messages into them as soon as possible so that the Inbox stays small.
Leaving the Preview Pane open in combination with opening directly to the Inbox can result in a slower startup. You can turn the Preview Pane off under View| Layout, or add the Preview button to the OE toolbar to toggle the pane on and off with a single click.
Sometimes removing or disabling Windows (or MSN) Messenger causes OE to open slowly. This will shown by an entry in the system error log: The server {FB7199AB-79BF-11D2-8D94-0000F875C541} did not register with DCOM within the required timeout. To fix this, open Regedit and navigate to this key:
HKEY_CLASSES_ROOT
\CLSID
\{FB7199AB-79BF-11d2-8D94-0000F875C541}
\InProcServer32
In the right-hand pane, double-click on the (Default) value and delete whatever is entered there, leaving it blank. Click OK. Now perform exactly the same step with the key directly underneath, namely
HKEY_CLASSES_ROOT
\CLSID
\{FB7199AB-79BF-11d2-8D94-0000F875C541}
\LocalServer32
Once both (Default) values are empty, OE will open normally.
OE very slow when starting, and Internet Explorer forms slow
This is an indication of missing or corrupt settings or files for the Protected Storage Service. This is a Windows service that allows you to save passwords for your Identities. This MS Knowledge Base article describes the problem and gives several possible solutions:
If the suggestions in the KB article do not solve the problem, you might also need to replace the Protected Storage files.
OE very slow when working in a news account
The usual cause is a very large local file with many news headers, even if marked as read and hidden from view. When you notice a group getting slower, it's time to clean up your newsgroups and compact your folders.
If the performance is slow when first opening a newsgroup, and when switching between newsgroups, it could be because the news account has a very large number of newsgroups. This is seldom a problem on systems with lots of memory, or on accounts with less than 25,000 or so newsgroups. If you suspect this is your problem, you can try my workaround.
OE slow to open, slow to switch mail folders, slow in everything
This could be caused by a bloated Folders.dbx file. Compact your folders to see if performance improves. If not, run Scan Disk followed by Disk Defragmenter. If performance is still slow, rename or delete Folders.dbx. Please read the consequences of doing this first.
Another possible source is a corrupt or missing Protected Storage Service.
Replace the Protected Storage Service (Pstore)
This procedure applies only to Windows95 and Windows98.
psbase.dll
pstorec.dll
pstorerc.dll
pstores.exe
extract /a ie_s4.cab ie_4.cab
extract /a ie_s4.cab ie_5.cab
extract /a ie_4.cab ps*.*
Since the ie_4.cab and ie_5.cab are not normally in the setup folder outside of their "containers", I suggest you now delete them using these:
delete ie_4.cab
delete ie_5.cab
Under Win98, you can also open the cab files directly to extract the files, or
you can use Winzip and similar programs under any version of Windows. However
in that case you will need to open ie_s4.cab, and then open the ie_4.cab that
it contains in order to extract the files. On some versions of IE5.5, only 3 of
the files are in ie_4.cab. In that case, you must also open the ie_s5.cab, open
the contained ie_5.cab and then extract the final pstore file.
Special thanks to Kyle Brant for helping me with the intricacies of extracting files from CABs within CABs.
This is almost always a sign of folders in need of compaction and/or a fragmented disk. Clean up your newsgroups, compact your folders, then run Disk Defragmenter (Start| Programs| Accessories| System Tools).
This article has moved to the Errors page.