Error Message: Error 745: An Essential File Is Missing

• Microsoft Windows 95
• Microsoft Windows OEM Service Release version 2
• Microsoft Windows 98

SYMPTOMS

When you attempt to connect to a remote computer using Dial-Up Networking, you may receive the following error message:

Error 745: An essential file is missing.
Re-install Dial-Up Networking.

CAUSE

This error message can occur when a Dial-Up Networking dynamic-link library (.dll) file is missing or damaged.

RESOLUTION

WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk.

For information about how to edit the registry, view the "Changing Keys and Values" Help topic in Registry Editor (Regedit.exe) or the "Add and Delete Information in the Registry" and "Edit Registry Data" Help topics in Regedt32.exe. Note that you should back up the registry before you edit it. If you are running Windows NT, you should also update your Emergency Repair Disk (ERD).
To resolve this issue, remove and reinstall Dial-Up Networking:

1. Click Start, point to Settings, and then click Control Panel.



2. Double-click Add/Remove Programs.



3. Click the Windows Setup tab, click Communications, and then click Details.



4. Click the Dial-Up Networking check box to clear it, click OK, and then click OK again.



5. Click Start, click Shut Down, click Restart Your Computer, and then click Yes.



6. Click Start, point to Programs, and then click Windows Explorer.



7. If it exists, rename the Rasapi32.dll file located in the Windows\System folder. For information about how to rename a file, click Start, click Help, click the Index tab, type renaming, and then double-click the Renaming files topic.



8. Use Registry Editor to check the path value under the following registry key:

   HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\RemoteAccess\Authentication\SMM_Files\PPP

   If the path reads Rasapi32.dll or SMMscrpt.DLL, perform steps 9-15. If the path reads other than Rasapi32.dll or SMMscrpt.DLL, edit the path to read Rasapi32.dll, extract a new copy of the Rasapi32.dll file, reinstall Dial-Up Networking, and skip the remaining steps.
   
   Extract a new copy of the Rasapi32.dll file from your original Windows 95/98 CD-ROM or floppy disks into the Windows\System folder. To do this, use the appropriate method:

   Extracting Rasapi32.dll from the Windows 95 CD-ROM

   1. Click Start, point to Programs, and then click MS-DOS Prompt.
   
   
   
   2. Type cd\, and then press ENTER.
   
   
   
   3. Insert the Windows 95 CD-ROM into the CD-ROM drive, and then close the Windows 95 screen if it appears.
   
   
   
   4. Type the following line at the command prompt, and then press ENTER
      
      extract /a drive:\win95\win95_02.cab rasapi32.dll /l c:\windows\system
      
      where drive is the drive letter assigned to your CD-ROM drive.
   
   
   
   5. Type exit, and then press ENTER to return to Windows.
   
   
   

   Extracting Rasapi32.dll from the Windows 95 Floppy Disks

   1. Click Start, point to Programs, and then click MS-DOS Prompt.
   
   
   
   2. Type cd\, and then press ENTER.
   
   
   
   3. Insert disk 10 of the Windows 95 disks into the floppy disk drive.
   
   
   
   4. Type the following line at the command prompt, and then press ENTER
      
      extract /a drive:\Win95_10.cab rasapi32.dll /l c:\windows\system
      
      where drive is the drive letter assigned to the floppy disk drive the Windows 95 floppy disk is located in.
   
   
   
   5. Type exit, and then press ENTER to return to Windows.
   
   
   

   Extracting Rasapi32.dll in Windows 98

   Extract a new copy of the Rasapi32.dll file from your original Windows 98 CD-ROM into the Windows\System folder using the System File Checker tool. To start the System File Checker tool, click Start, click Run, type sfc.exe in the Open box, and then click OK. For more information about using the Extract tool, click Start, point to Programs, click MS-DOS Prompt, type extract, and then press ENTER. For more information about using the Extract tool or System File Checker, please click the article number below to view the article in the Microsoft Knowledge Base:

   Q129605 How to Extract Original Compressed Windows Files




9. Use Registry Editor to delete the SMM_Files key under the following registry key:

   HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\RemoteAccess\Authentication




10. Click Start, click Settings, and then click Control Panel.



11. Double-click Add/Remove Programs.



12. Click the Windows Setup tab, click Communications, and then click Details.



13. Click the Dial-Up Networking check box to select it, click OK, and then click OK again.



14. When you are prompted to restart your computer, click Yes.



15. If you had previously installed Dial-Up Scripting in Windows 95, rename the Smmscrpt.dll file in the Windows\System folder, and then reinstall Dial-Up Scripting.
    
    For information about installing Dial-Up Scripting, please click the article number below to view the article in the Microsoft Knowledge Base:

    Q153038 How to Automate Dial-Up Networking Connections

MORE INFORMATION

To determine the DLL file used by Dial-Up Networking, view the Path value under the following registry key:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\RemoteAccess\Authentication\SMM_Files\PPP

Additional query words: msnetwork msn

Keywords : kberrmsg dun win95 win98
Version : WINDOWS:95
Platform : WINDOWS
Issue type : kbprb