There may be an issue with how your hard drive is configured or connected to your computer.
What happens if you use the Project Archiver to move one of your projects, along with its media, back to an internal drive? Then can you open it?
Welcome to the forum.
When using external HDD's, whether to edit to/from, or for archiving, I set the drive letter for each external HDD to a unique drive letter, in the OS of all machines. This ARTICLE goes into more detail.
I agree with Steve, that it appears that there is an issue with the external HDD.
PrE uses absolute Paths to link to everything in the PREL, and if any part of that Path changes, PrE hits a wall. Usually, the PREL will Open fine, but then PrE will ask "Where is file _____ ?" for the linked media. It appears that you are not getting to that point, and are encountering a drive error first.
I copied one of the folders to the internal HD of a different computer that orginally created the archive. Then I tried to open newly copied prel and received the same error message.
Do ALL the computers running PRE need to have the prefences all set the same; like swap file, encoded file, etc????
I am now afraid that my archived files may not operate properly.
Did not work.
I have no idea why this is happening, John. And I've never heard of the Project Archiver corrupting project files.
As long as you are trying to open your project file with the same version of the program that created the original project, it should work.
Otherwise, I'm afraid you may have to contact Adobe Tech Suport. Your issue may be too deep for us to troubleshoot here on this forum.