Error 745: An Essential File Is Missing

The following error message may be displayed on your Windows 95 or Windows 98 computer when you try to connect it to a remote computer using Dial-Up Networking:

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

Cause Of the Error

You encounter this error message when a required Dial-Up Networking Dynamic Link Library (DLL) file is either corrupt or missing from the system.

Resolution Methods

You can resolve the error by performing the following steps:

Warning: The steps discussed below require you to edit the registry. Because the registry is an essential component of your Windows operating system, you must be very careful while making these edits. It is recommended that you backup the registry before making any changes to it. You can do this by using the File > Export command in the registry editor. You may also use a reliable registry cleaner tool to do the task.

  1. Open Start menu, select Run, type Appwiz.cpl and then press Enter.
  2. On the Windows Setup tab, click on Communications, and then click the Details button.
  3. Clear the Dial-Up Networking check box, and then click OK twice.
  4. Restart your Windows computer when prompted.
  5. After the computer restarts, open Windows Explorer.
  6. Locate the “Rasapi32.dll” file in the C:\Windows\System folder.
  7. Open Start menu, select Run, type regedit and then press Enter.
  8. In the Registry Editor window navigate to the following registry key:

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

  9. Double-click on the Path key in the right pane.
    • If the path refers to Rasapi32.dll or Smmscrpt.dll, perform the following steps:
    1. In the Registry Editor window, delete the SMM_Files key from the following registry key:

      2. HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\RemoteAccess\Authentication

    2. Exit the Registry Editor.
    1. In the Value Data field of the Path key, change the value to Rasapi32.dll.
    2. Now, extract a new copy of Rasapi32.dll from your Windows 95 or Windows 98 installation CD-ROM or Floppy disk to the C:\Windows\System32 folder.
    • If the path is not Rasapi32.dll or Smmscrpt.dll, perform the following steps:

    10. On Windows 95

    Open MS-DOS Prompt, type cd\ and then press Enter. Next, insert the Windows 95 installation CD in the CD drive or insert Windows 95 installation floppy disk 10 in the floppy drive. Type the following command and then press Enter.

    extract /a CD_or_Floppy_drive_letter:\Win95_10.cab rasapi32.dll /l c:\windows\system

    Finally, restart your Windows95 system.

    On Windows 98

    On your Windows 98 computer, open Start menu, select Run, type sfc.exe and then press Enter. Insert your Windows 98 CD-ROM in the CD drive. Select Extract one file from installation disk. Next, in the Specify the system file you would like to restore box, type C:\Windows\System32\rasapi32.dll and then click Start. In the Restore from box, specify the path to your Windows 98 installation files on the CD (cd_drive:\Win98) and specify C:\Windows\System32\ in the Save file in box and then click OK. After the installation is done restart your Windows 98 system.

  10. Finally, to reinstall Dial-Up Networking, open Start menu, select Run, type Appwiz.cpl and then press Enter.
  11. Select the Dial-Up Networking check box, and then click OK twice.
  12. Restart your Windows computer when prompted.

To prevent files and registry entries from getting damaged, it is recommended that you regularly clean your registry with the help of a reliable registry cleaner tool, such as RegServe.