MS Outlook has become a medium of interchanging information in the form of emails by all types of organizations. Users of any organization are connected with each other using Outlook due to its communication specific and personal information storing capabilities.

Many users using the Outlook are very dependent on it. The data of MS Outlook stored in system is in PST format. PST file is the first thing to look for when planning to backup of the entire Outlook data.

Many errors can disturb the working of Outlook and resist the workflow of the users. These errors also restrict the accessibility of PST files; outllib.dll is one of the errors, which disturb the working of Outlook, and makes PST file inaccessible in the worst of scenarios.


Outllib.dll is a file or a module that resolves the internal problems of Outlook. .dll file is very similar to .exe files.

It tackles the internal problems and issues of Outlook:

  • User getting two dial up connection while connecting to Exchange server
  • Correct display of customized .msg files
  • Turning off the option of comma as separator
  • Outllib.dll consists of ReplytoAll command that helps to repair

Prevent Invalid Page Fault Error & Its effects on Outlook

When Outlook starts showing error “Outlook caused an invalid page fault in module OUTLLLIB.DLL”, it means that there is some problem in the DLL (Dynamic Link Library) file. The error is caused due to the damage or deletion of DLL file.

Impact of Invalid Page Fault (IPF) on MS Outlook

Invalid page fault error has a very strong impact on MS Outlook. It stops the smooth working of Outlook. It puts Outlook in a freezing state; users cannot use the services of Outlook.

How to Remove Invalid Page Fault (IPF)?

Error in Invalid Page Fault can be solved by renaming or resetting the two files outcmd.dat and extend.dat.

Follow the given steps to prevent the PST corruption with the help of outcmd.dat:

1. Exist the Outlook

2. Open the search utility and select the file folder

3. Enter outcmd.dat in search dialog and initiate the search

4. When searching is completed, locate outcmd.dat

5. Click the outcmd.dat and rename the file

6. Rename the file .dat to .old

7. Press Enter

8. Close the dialog box

9. Re open the Outlook

If there is no issue in Outlook after renaming the file, then it is confirmed that the problem is resolved. But if again there is an issue in restarting Outlook then users can rename the extend.dat file too.

Alternate Solution

For renaming or resetting the extend.dat file, users can follow the same steps that are used in renaming the outcmd.dat file. User can rename the extend.dat file to extend.old and check the working of Outlook.

Sometimes renaming operation fails to resolve Invalid Page Fault (IPF) error and it starts damaging the contents of an Outlook profile, i.e. PST file. 

A Dependable Solution: In that case, user can opt for third party tools. A number of tools recover PST file. Outlook PST File Recovery is one of the tools that helps user to recover damaged PST files. It recovers the highly damaged PST files and makes them accessible. The tool is featured with number of features like it can recover hard deleted items of PST files, can recover password protected PST files, gives advance options for filtering the data and more.