Whether you are working in Visual Basic or you have taken the time to work in other programs, there is a chance that you may have run into a runtime error 91. When you encounter a runtime error 91, you may discover that there are a number of different issues that may have caused it. For instance, you might discover that perhaps you may be forced to end a program without saving your work prior, or the several programs that you're running might decide to crash all at the same time. This may even cause your computer to hang, and you may lose whatever unsaved data you might have been working on.

The first thing that you should consider when you experience a runtime error 91 is to run your antivirus program. The error may be indicative of a malicious application on your computer that's causing your other applications to crash, and you will need to be rid of it immediately. There are a variety of viruses and even adware that can get on your computer that may result in a runtime error 91. Find out what's lurking in your computer and sort out the malicious files with your antivirus program. It's easy enough to do, and keeping your antivirus up to date so that it can identify newer strains of viruses is just as simple.

Remember that as long as your computer is hooked up to the internet, it is vulnerable to the multitudes of malicious applications such as viruses and ad-ware. Take the time to look into the many different antivirus and anti-adware programs out there on the internet. Find the most comprehensive and intuitive program that is right for you and your needs. There are free programs for you to download, but paying for a more reliable antivirus or anti-adware program might not be so bad either. Get the tools that you need, and make sure that you are following good virus removal procedures.

Once you have your antivirus program, there are several steps that you will need to take before you can ensure an effective clean. Make sure your antivirus is kept up to date with the latest version of virus definition files. Then you need to ensure that you're not connected to the internet, by simply removing the connection cable from the computer. Now that your computer is no longer connected to the internet and vulnerable to more malware, boot up your computer in safe-mode. In safe mode, you will find that a lot of the programs that viruses that cause the runtime error 91 will be more exposed and thus far easier to remove. Run your antivirus programs until you come up with no results and then restart your computer and see if you are still getting the errors.

Though there may be several causes for the runtime error 91, remember that you are looking at something which is often caused by virus issues. Take the time to prevent further incidences of a viral infection by protecting yourself with a firewall, and make sure that you run virus scans regularly and frequently.