You receive a "VBScript Runtime Error '800A01A8'" error message in OWA

When you try to access a client mailbox by using Microsoft Outlook Web Access (OWA), you may receive the following error message:

This problem may be caused by a variety of factors, including incorrect permissions on required files for the OWA client, registry changes, or damaged files. This article discusses how to troubleshoot this problem.

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base: To troubleshoot this problem, follow these steps:

1. Verify that the permissions on Cdohtml.dll are correct. Users must have READ permissions to this DLL. This file is responsible for rendering all the ASP pages with OWA. To check the permissions:
   1. Right-click the file name, and then click Properties.
   2. Click the Security tab, and then click Permissions.
      
      Cdohtml.dll is typically located in the Exchsrvr\Bin directory. Make sure that all users have at least READ permissions to this directory.
2. Check the registry. You may have a problem with one of the following registry subkeys:
   • If you have OWA 5.5 or OWA 5.5 SP1 installed, the problem may be with the following subkey:
     HKEY_CLASSES_ROOT\TypeLib\{BC00F700-31AC-11D0-B5F1-00AA00BF3382}
   • If you have OWA 5.5 SP2 or later installed, the problem may be in one or more of the following subkeys:
     HKEY_CLASSES_ROOT\CLSID\{bc00f780-31ac-11d0-b5f1-00aa00bf3382}
     HKEY_CLASSES_ROOT\CLSID\{bc00f781-31ac-11d0-b5f1-00aa00bf3382}
     HKEY_CLASSES_ROOT\CLSID\{bc00f782-31ac-11d0-b5f1-00aa00bf3382}
     HKEY_CLASSES_ROOT\TypeLib\{BC00F700-31AC-11D0-B5F1-00AA00BF3382}
   These are the subkeys for Cdohtml.dll. You can export each of these subkeys and then run Regsvr32.exe on the DLL to register each key back into the registry correctly. To export and remove the registry subkey, follow these steps:
   1. Click Start, click Run, type regedit to start Registry Editor, and then click OK.
   2. In Registry Editor, select the key that you want to back up.
   3. On the Registry menu, click Export Registry File.
   4. In the Save In list, select the folder where you want to save the backup.
   5. In the File Name box, type a name for your backup file, such as Options or Backup.
   6. Under Export Range, click Selected branch.
   7. Click Save. The file is saved with a .reg extension.
   8. Select the subkey that you want to remove.
      • If you have OWA 5.5 and OWA 5.5 SP1 installed, select the following subkey:
        HKEY_CLASSES_ROOT\TypeLib\{BC00F700-31AC-11D0-B5F1-00AA00BF3382}
      • If you have OWA 5.5 SP2 or later installed, select all the following subkeys:
        HKEY_CLASSES_ROOT\CLSID\{bc00f780-31ac-11d0-b5f1-00aa00bf3382}
        HKEY_CLASSES_ROOT\CLSID\{bc00f781-31ac-11d0-b5f1-00aa00bf3382}
        HKEY_CLASSES_ROOT\CLSID\{bc00f782-31ac-11d0-b5f1-00aa00bf3382}
        HKEY_CLASSES_ROOT\TypeLib\{BC00F700-31AC-11D0-B5F1-00AA00BF3382}
   9. Press DELETE. Alternatively, right-click each subkey, and then click Delete.
   10. Quit Registry Editor.
       
       When you are finished, stop the WWW Service by using either the Services component in Control Panel or the Internet Information Services (IIS) Manager. Then you must re-register Cdohtml.dll. To do so, follow these steps:
       1. Click Start, and then click Run.
       2. Type regsvr32 c:\exchsrvr\bin\cdohtml.dll , and then click OK.
   11. After you re-register the Cdohtml.dll file, you may have to verify the permissions on the registry subkeys. To verify the permissions, follow these steps:
       1. Open Registry Editor.
       2. Locate the following registry subkeys:
          HKEY_CLASSES_ROOT\CLSID\{bc00f780-31ac-11d0-b5f1-00aa00bf3382}
          HKEY_CLASSES_ROOT\CLSID\{bc00f781-31ac-11d0-b5f1-00aa00bf3382}
          HKEY_CLASSES_ROOT\CLSID\{bc00f782-31ac-11d0-b5f1-00aa00bf3382}
          HKEY_CLASSES_ROOT\TypeLib\{BC00F700-31AC-11D0-B5F1-00AA00BF3382}
       3. Click each subkey, click Security, and then click Permissions.
       4. Assign the Everyone group Full Control permissions to the registry subkeys.
       5. Assign the IUSR_ServerName account Full Control permissions to the registry subkeys.
   12. Restart the WWW Service.
3. Confirm whether there is an apostrophe in the name of the directory where OWA was installed. If this is the case, remove the OWA component and reinstall it in a different directory. For additional information about how to remove and reinstall OWA, click the following article number to view the article in the Microsoft Knowledge Base:
   290287 � XCCC: How to completely remove and re-install OWA
4. There may be a problem with the installation of Transaction Server. Transaction Server processes all IIS virtual directories that are running as programs. To resolve this problem, do the following:
   1. Start the IIS Microsoft Management Console (MMC) snap-in, and then open the Transaction Server folder.
   2. Click Computers, click My Computer, click Packages Installed, click IIS In-Process Applications, and then click Components.
   3. Delete the IISWAM.1_Root_Exchange component.
   4. Click the Internet Information Server folder, and then click Default Web Site.
   5. Right-click the Exchange virtual directory, and then click Properties.
   6. Click the Virtual Directory tab.
   7. Under the Application Settings section, click Remove, click Apply, and then click OK.
   8. In Control Panel, double-click Services, and then stop the IIS Admin Service.
      
      Note This also stops the FTP Publishing Service and the Web Publishing Service.
   9. Click the Internet Information Server folder, and then click Default Web Site.
   10. Right-click the Exchange virtual directory, and then click Properties.
       
       The Configuration and Unload buttons are unavailable.
   11. Click Create.
   12. Click Apply, and then click OK.
   13. In Control Panel, double-click Services, and then start the IIS Admin Service, the FTP Publishing Service, and Web Publishing Service.
5. If Transaction Server is not installed, you may still be experiencing a problem with the application settings. In this case, follow steps 4-e through 4-m of this procedure.
6. This problem may also occur if you installed OWA on a server that is also running one or more of the following programs:
   • Microsoft FrontPage 98
   • Microsoft FrontPage 2000
   • Microsoft Visual Studio 6.x
   • Microsoft Visual InterDev
   • Seagate Crystal Reports
   To resolve this problem, follow these steps:
   1. Open Control Panel, double-click Add/Remove Programs, and then remove the programs that are listed in the previous section.
   2. Insert the Microsoft Exchange Server 5.5 CD-ROM into the CD-ROM drive, and then click Add/Remove components.
   3. Click to clear the Outlook Web Access check box to remove the OWA component.
   4. Run the Exchange 5.5 Setup program to reinstall the OWA component.
   5. Reapply your current Exchange 5.5 service pack.
   6. Reinstall your development programs.
7. Remove and reinstall the OWA component. For additional information about how to remove and reinstall OWA, click the following article number to view the article in the Microsoft Knowledge Base:
   290287� XCCC: How to completely remove and re-install OWA