Rundll32.exe is a process that executes DLLs and places their libraries into the memory so that they can be used more efficiently by applications. This program is important for the stable and secure running of your computer and should not be terminated. Check and ensure that the particular rundll.exe is situated in the WinSxS, System32 or SysWOW64 folders. If so, it is the legitimate Microsoft process; else it could be a virus.
The following is, primarily, based on the fruitful discussion at TechNet, and the important points have been culled out from there and presented here.
Windows Host Process (Rundll32) has stopped working
If you get this error message frequently, here are a few troubleshooting steps you may try:
Fix Rundll32.exe error
1] Update Windows
First and foremost, ensure that your Windows is fully updated.
2] Turn off Thumbnails view
If you get the error when opening folders that contain video files, turn off the thumbnails view and see if it helps:
Open Control Panel > Folder Options > Always show Icons, Never Thumbnails
3] Check program installations
Try to remember, when did this error start popping up.
Was it after installing a particular program? Was it after installing, say, Nero ? if yes try this:
Open Computer > System Drive > Program files > Common Files > Ahead > DSfilter. Rename “NeroVideoProc.ax” to say “1NeroVideoProc.ax”. Also rename “NeVideo.ax” to say “1NeVideo.ax”
Maybe you could update or uninstall Nero software and see if it helps.
4] Update Codec Pack
The Intel ViiV software and the K-Lite Codec Pack too are known to cause this problem. If you have installed any of them, update them or uninstall them and see if it helps.
5] Troubleshoot in Clean Boot State
Follow these steps to try and find out, which software is causing this issue.
Run msconfig to open up the System Configuration Utility window. Click on Services, and check the “Hide all Microsoft services” checkbox. Click on “Disable All” button.
Now click on the “Startup” tab, and then click on “Disable All” button again. Press the OK button and then “Restart” button on the following window.
Effectively, you have turned off all non-Microsoft services and startups.
If the issue is resolved, open System Configuration Windows again and then enable all the services from Services tab and then check the issue after restarting the computer in the same way as mentioned above disabling one service at a time.
6] Disable DEP
Turn off Data Execution Prevention and see if it helps. But remember that this is a security feature that is there to help protect your computer.
7] Run Troubleshooter
Run the Microsoft Windows File and Folder Troubleshooter and see if it helps.
This way, you will have to enable/disable services and start-ups to narrow down on the culprit. Agreed, this is a lengthy and painfully boring process, but it will help you identify the culprit.
This post will help you if you receive Windows Shell Common Dll has stopped working message.