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March 16, 1998

A little 32-bit mail file can have a big effect on your PC -- but here's a fix

Sometimes the simplest things lead to big troubles. Reader Michael Gove of El Segundo, Calif., writes that he recently updated his version of Microsoft Internet Explorer and Outlook Express -- fair enough. But it soon became clear that his address book and mail merge features in Microsoft Word 7.0 no longer worked.

Fortunately for Gove, an error message pointed him to a solution. He found that the shared file MAPI32.DLL (Microsoft's 32-bit mail API) appeared both in the error message and in his Windows\System folder with a new date corresponding to his Explorer upgrade. Replacing the new version with the original file from a backup solved the problem.

But this little file has a much bigger impact than just a simple error message on a single user. Microsoft reports that installing its Exchange Update -- which is part of Windows 95's Service Release 1 -- can give you a version of MAPI32.DLL that conflicts with other software.

The Exchange Update is a fix that a number of new Windows 95 users found themselves very interested in when they migrated from Windows 3.1x. As shipped in the Windows 95 box, Exchange cannot view the shared folders in the post offices created by Windows for Workgroups 3.x and Microsoft Mail 3.x.

Microsoft provides the Exchange Update to correct this. You download the update by pointing your browser to Running the update writes to your hard disk new files that update Exchange.

The problem arises if you run the file from your Windows folder or your Desktop. These seem like two reasonable places to put a new Windows file. But if you do so, according to Microsoft, this results in "creating the version conflict." (For more details, see and Instead of using the Windows folder or your Desktop to run this file, you should create a temporary scratch folder and run it from there. If you already ran EXUPDUSA.EXE on the Desktop, delete the following eight files from there now: MAPI32.DLL, MAPI.DLL, MSFS32.DLL, EXCHG UPG.INF, EXCHNG32.EXE, READ ME.TXT, WGPOADMN.DLL, and WMSUI32.DLL.

Symptoms of the problem include the Tools menu and the Deliver Now command being disabled in Microsoft Exchange, or Windows crashing entirely.

Microsoft also says that MAPI32.DLL is involved in a snafu in which some PC manufacturers installed the retail version of Windows 95 but enclosed Windows Service Release 1 on the CD-ROM that shipped with the systems (or vice versa).

When users run the Add/Remove Programs control panel to add a component, they receive an error message about "older files" being copied to their system -- including MAPI32.DLL. Microsoft recommends that you contact the vendor. See

If you're having MAPI32.DLL problems but don't have a backup like reader Gove, first copy the EXTRACT.EXE file from your Windows 95 disk to your C:\Windows folder. Then use the following command at a DOS prompt (all on one line), where X: is the drive in which the Windows CD-ROM or setup diskette is located, to restore your original MAPI32.DLL:


Gove will receive a copy of Windows 95 Secrets for reporting to me his problems and the fix.

Brian Livingston is the co-author of several best-selling Windows books, including the most recent Windows 95 Secrets (IDG Books). Send comments to Unfortunately, he cannot answer individual questions.

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