Files automatically renaming themselves, duplicate file names

I have a new laptop, so unless this is some weird feature that's specific to the laptop, then I assume it's a Windows 10 settings issue because I've never encountered anything like this before. I downloaded several JPGs and PDFs from various emails and began to change the arbitrary "234809238ksdfjskdfjsdlkf" type filenames to specific things indicating what they are, and I got done and realized all the stuff I typed was gone and the JPGs had changed to "filename(1)", "filename(2)", "filename(3)" and the same with the PDFs.. and "filename" was the name I'd assigned to the first file of each file type. The subsequent names I'd chosen were entirely different and the files were all unrelated to one another.

I figured I'd go ahead and ask and try to get this issue resolved before it happens in the future and really pisses me off.

Sounds to me it is either some security software intervening or some bizarre bug in the email program you are using. Certainly not something Windows itself would do. Least I never seen it do that.

I just have Windows Defender. Well, and malwarebytes but that shouldn't be doing anything. I was using gmail website.

abc123:
I have never seen anything like this at all. Never heard of such a thing. Must be something on that specific laptop.
Best to you. What OS is on that laptop? tks,,, Cliff M.

Windows 10. (well I upgraded from 8.1 and did a clean install)

It's an HP Spectre x360

may be malware baby , better instal internet security suite and scan

my advice for future use comodo firewall it is best
not even need to install anti virus bz it has cloud based virusscope

"I downloaded several JPGs and PDFs from various emails and began to change..."

Hi, perhaps if you explain precisely how you renamed the files it might be clearer.

I assume given that statement you were working in File explorer (or equivalent) when you renamed the files, and you had a list of files shown in one folder which you had open.
You then manually renamed each one by clicking on the filename, waiting, clicking again, then typing the new name.

If so, you were working on one file at a time. At what point did you see the file names change?

Or, do you in fact mean that you tried to change the name of each in a 'Save as' box?

Or sthg else?

And how is your email handled? via your browser or an email client?
Thanks!