"Microsoft Outlook cannot install the necessary files due to Windows Installer error 1605" error message when you start Outlook 2002

When you start Outlook 2002, you may receive the following error message: If you start Outlook in Safe Mode (by using the /safe command-line switch), you still receive the error message.

For additional information about a similar issue that has a different cause, click the article number below to view the article in the Microsoft Knowledge Base:

This issue may occur if your installation of Outlook has become corrupted.

Before you continue with these steps, see the following article in the Microsoft Knowledge Base to confirm the cause of this issue:
To resolve this issue, follow these steps:

NOTE: Because there are several versions of Microsoft Windows, the following steps may be different on your computer. If they are, see your product documentation to complete these steps.

Step 1 - Remove Outlook

To remove Outlook, follow these steps:

1. Close all Microsoft Office programs, and turn off any antivirus software.
2. Click Start, and then click Control Panel.
3. Click Add or Remove Programs, and then do either of the following:
   • If you have Outlook installed without Microsoft Office, click to select Microsoft Outlook 2002, and then click Change.
     
     -or-
   • If you have Outlook installed as part of Microsoft Office, click to select Microsoft Office XP, and then click Change.
4. Click Add or Remove Features, and then click Next.
5. Click the icon to the left of Microsoft Outlook for Windows, and then click Not Available.
6. Click Update, and then follow the remaining steps to remove Outlook.

Step 2 - Rename Outlook Files

1. Click Start, click Search, and then click All files and folders.
2. In the All or part of file name box, type outl*.dll.
3. In the Look in box, click Local Hard Drives.
4. Click Search Now.
   
   The Search should find the following files:
   
   C:\Program Files\Microsoft Office\Office10\Addins\OUTLVBA.DLL
   C:\Program Files\Microsoft Office\Office10\1033\OUTLCMR.DLL
   C:\Program Files\Microsoft Office\Office10\1033\OUTLLIBR.DLL
   C:\Program Files\Microsoft Office\Office10\1033\OUTLWVW.DLL
   C:\Program Files\Microsoft Office\Office10\Outlwab.dll
   C:\Program Files\Microsoft Office\Office10\Outlacct.dll
   C:\Program Files\Microsoft Office\Office10\Outlas.dll
   C:\Program Files\Microsoft Office\Office10\Outlcm.dll
   C:\Program Files\Microsoft Office\Office10\Outlctl.dll
   C:\Program Files\Microsoft Office\Office10\Outllib.dll
   C:\Program Files\Microsoft Office\Office10\Outlmime.dll
   C:\Program Files\Microsoft Office\Office10\Outlph.dll
   C:\Program Files\Microsoft Office\Office10\Outlrpc.dll
   C:\Program Files\Microsoft Office\Office10\Outlvbs.dll
5. Right-click each file, click Rename, rename the file, and then press ENTER. For example, rename the files as follows:
   Outlvba.old
   Outlcmr.old
   Outllibr.old
   Outlwvw.old
   Outlwab.old
   Outlacct.old
   Outlas.old
   Outlcm.old
   Outlctl.old
   Outllib.old
   Outlmime.old
   Outlph.old
   Outlrpc.old
   Outlvbs.old
6. Repeat steps 1 through 5 to rename additional Outlook files. Use the Search feature to search for and then rename all the following:
   Mapisvc.inf
   Outlook.exe
   Ems*.*
   Extend.dat
   Outcmd.dat
   Frmcache.dat
   
   For example, to rename all these files, follow these steps:
   1. In the Search for files or folders named box, type mapisvc.inf, and then rename the following file that is found:
      C:\Program Files\Common Files\System\Mapi\1033\Mapisvc.inf
   2. In the Search for files or folders named box, type outlook.exe, and then rename the following file that is found:
      C:\Program Files\Microsoft Office\Office10\Outlook.exe
   3. In the Search for files or folders named box, type ems*.*, and then rename the following files that are found:
      C:\Program Files\Common Files\System\Mapi\1033\Emsabp32.dll
      C:\Program Files\Common Files\System\Mapi\1033\Emsmdb32.dll
      C:\Program Files\Common Files\System\Mapi\1033\Emsui32.dll
      
   4. In the Search for files or folders named box, type extend.dat, and then rename the following files that are found:
      C:\Documents and Settings\username\Local Settings\Application Data\Microsoft\Outlook\Extend.dat
   5. In the Search for files or folders named box, type outcmd.dat, and then rename the following file that is found:
      C:\Documents and Settings\username\Application Data\Microsoft\Outlook\Outcmd.dat
   6. In the Search for files or folders named box, type frmcache.dat, and then rename the following file that is found:
      C:\Documents and Settings\username\Local Settings\Application Data\Microsoft\FORMS\Frmcache.dat

Step 3 - Remove Outlook Registry Keys

WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

NOTE: Back up your registry before you follow these steps.

1. Click Start, and then click Run.
2. In the Open box, type regedit, and then press ENTER.
3. Locate and then click the following key in the registry:
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Exchange
4. On the Edit menu, click Delete, and then click OK when the following confirmation message appears:
   Confirm Key Delete
   Are you sure you want to delete this key and all of its subkeys?
5. Locate and then click the following key in the registry:
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Schedule+
6. On the Edit menu, click Delete, and then click OK when the confirmation message appears.
7. Locate and then click the following key in the registry:
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office\10.0\Outlook
8. On the Edit menu, click Delete, and then click OK when the confirmation message appears.
9. Locate and then click the following key in the registry:
   HKEY_CURRENT_USER\Software\Microsoft\Office\10.0\Outlook
10. On the Edit menu, click Delete, and then click OK when the confirmation message appears.
11. Quit Registry Editor, and then restart the computer.

STEP 4 - Reinstall Outlook

To install Outlook, follow these steps:

1. Click Start, and then click Control Panel.
2. Click Add or Remove Programs, and then do either of the following:
   • If you have Outlook installed without Microsoft Office, click to select Microsoft Outlook 2002, and then click Change.
     
     -or-
   • If you have Outlook installed as part of Microsoft Office, click to select Microsoft Office XP, and then click Change.
3. Click Add or Remove Features, and then click Next.
4. Click the icon to the left of Microsoft Outlook for Windows, and then click Run all from My Computer.
5. Click Update, and then follow the remaining steps to install Outlook.