A Microsoft Visual C++ Runtime Library Runtime Error can occur if a program conflicts with the Mosdmn.exe and Mosearch.exe files. These two files are part of the ‘support for fast searching’ feature which is included within Microsoft Office. Fast searching enables the Indexing Service in Office to create a catalogue of Office files on your computer’s hard disk.


There are two possible resolutions to this problem, both of which require some downloads and installations to your computer.

The first one is to use a piece of boot cleaning software, such as MoSearch. Firstly, download the program, and then go to Start > Run. In the search box type “msconfig.exe” and then click OK. Once the dialogue window opens up then click on the ‘General’ tab, and then select ‘Selective startup’. Once this tab has opened up, clear every check box except for the one related to MoSearch. Click OK, and then select the ‘Yes’ option when prompted to restart the computer.

If when you continue to run your computer you still get the error message then you need to try the following.

Firstly, uninstall the ‘Support for Fast Searching’ feature which is built into the Microsoft Office suite. Firstly, quit out of any Office programs that you are currently running. Go to Start > Settings > Control Panel. Select the ‘Add/Remove Programs’ option and double-click it. (Note: these steps may differ very slightly depending on the version of Windows used, but they should be possible to follow without too many problems regardless of what edition of Windows you are using).

Next on the Install/Uninstall tab, click ‘Microsoft Office product’, where Office product is the name of the specific Office product in question. If you’re using a standalone version of the one of the programs within the Office suite then select this. Next click ‘Add/Remove’.

After this task has been completed, select the option marked ‘Maintenance Mode Options’, and in the dialog box that this opens up click on the ‘Add or Remove Features’ option before selecting ‘Next’.

You will then see a plus sign located next to ‘Office Tools’, point to the icon next to ‘Support for fast searching’, and then select ‘Not Available.’ And finally click update.

This completes the process for the Office program in question, however it may be necessary to go back and go over the same steps again for other Office programs that are running on your computer, until they’ve all been addressed.

Finally, use the Start menu search box to locate the the Mosearch.exe and Mosdmn.exe files. Once you have located them delete them from your computer.