Why is Photoshop CS3 saving .psd files as 09 files instead?

I couldn't find anything at all about 09 files, and I've never seen this before. When I go to "save as" and select ".psd", the files are instead saved as 09 files. Not .09, just 09, and then are not re-open-able with Photoshop. I can save as all other types of files (.jpg, .gif, .png,... show more I couldn't find anything at all about 09 files, and I've never seen this before. When I go to "save as" and select ".psd", the files are instead saved as 09 files. Not .09, just 09, and then are not re-open-able with Photoshop. I can save as all other types of files (.jpg, .gif, .png, etc.), but saving as a .psd simply will not work.

Any ideas on what could be wrong?
Update: And to answer the question below, no, I'm on a PC, not an Apple.
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