This is weird. I have an old hp pavilion dv6 laptop, allegedly windows xp media center edition version 2002 sp3. Yesterday I inserted two different flash drives each containing .xls files as well as other files. I didn't even bother opening the excel files.  I had copied them over from a win 7 pro 64 bit machine, and I am sure they were good. When I tried to eject the flash drives from the xp machine I got a message saying that a program was trying to access them. I stopped the drives again and the message went away. I am sure no files were open. When I tried to open the excel files again, I got a message from office saying they were corrupt and probably malicious. I tried to open them anyway and excel could only partially repair them, though they were still readable.

I scanned the xp laptop for viruses using malwarebytes and ms security essentials, nothing. But today I tried again with the same files and no problems. I checked the size of a good and bad file and they had the exact same number of bytes. I ran the comp command and ten bytes were different out of 70,144 bytes. So somehow the xp laptop corrupted that file by substituting bytes... If It is not a virus what could it possibly be, and how do I make sure that it doesn't happen again?
Each time I properly ejected both flash drives.

Oh, I say it is allegedly media center edition because I just ran sfc /scannow and it prompted me for a windows xp professional disk! Maybe that is the problem.. I got the laptop second hand and don't know what is going on as far as that, my computer says windows media edition. I also checked  manually for this cryptolocker virus but saw no evidence of it in the registry or in %appdata%.

Hi JamesFie,

Based on your description, you open the excel file from flash drive in Windows XP, but the file is damaged you cant open it.

I suggest you copy the file to local location, then repair this file and check if it works fine after repairing this office.

1. Click the Microsoft Office Button Office button image, and then click Open.
2. In the Open dialog box, select the corrupted workbook that you want to open.
3. Click the arrow next to the Open button, and then click Open and Repair.
4. Do one of the following:

To recover as much of the workbook data as possible, click Repair.

To extract values and formulas from the workbook when an attempt to repair the workbook is not successful, click Extract Data.

More information about repairing file please refer to this article:

https://support.office.com/en-za/article/Repairing-a-corrupted-workbook-7abfc44d-e9bf-4896-8899-bd10ef4d61ab

And you can also send this file to your Windows XP computer by Email and check if it works fine, maybe the flash drive occur your issue.

Hope its helpful.

Regards,

George Zhao
TechNet Community Support

You can Excel Repair Toolbox is effective solution to fix corrupt Excel workbooks and worksheets. For more: https://www.excelrepairtoolbox.com/