However, what about the many gigabytes of.dat files? Are these safe to delete, or will it cause your computer to crash?
The extension.dat stands for data file. These are used by many applications so you can't know what it stands for without knowing the application that created it. Thankfully, even if you don't recognize the extension, the following steps can help determine if any file type is safe to delete.
1. Back up the File: Copy it to a hard drive, CD, another computer, anything. Just make sure to save the file first so you can get it back if you actually needed it.
2. Rename the File: After you rename the file, (remember to record the original name), use different applications on the computer and then reboot. If an error occurs due to the missing file name, you know what the file did and you can decide if you need to replace it. If no error occurred, move on to the next step.
3. Delete the File: First, make sure you've saved the file in step #1. After that, delete the file in question. Then, use your computer for a while, reboot, and experiment with different applications. If an error occurs, you know what the file did and can assess the situation from there. If no error appears, you're probably off the hook. Still it is important to keep the back up. An error may occur later if the file is connected to an application you rarely use.
4. The computer may not allow you to delete or rename the file. This indicates the file does matter. Use a tool, such as Process Explorer, available from Microsoft's website, to learn which application is using it. Then you can decide if you need to keep the file.
Bottom Line? Always back up any file in question before you delete it and remember where you saved the back up. You will save a lot of unnecessary time and money if you need the file later on.
Get more free tech help and advice from Leo Notenboom by visiting http://ask-leo.com With over 30 years of industry experience, including an 18 year career as a software engineer with Microsoft, Leo gives real answers to real questions from ordinary computer users at Ask Leo! Subscribe to Leo's weekly newsletter now and receive a free ebook: "Internet Safety – Keeping Your Computer Safe on the Internet", a collection of steps, tools and concepts you need to know to keep your computer and your information safe.