XYplorer Beta Club

To reproduce:
1. select a folder
2. right click and "Create text file" to create a file 'con.txt'

Result:
error dialog "Bad Filename" and "This is not a valid filename"

hmm... it seems if a filename begins 'con.' then the error occurs.
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OS: Windows 11 Pro, 64-bit, Version 25H2, Build 26200.8457 (10.0), AMD64
XYplorer: 28.30.0600 (64-bit) - Standard License Professional
screen scaling 125%

That's not a bug in XY, that's what Windows prevents. Try the same in Windows Explorer, same result...

that's the daft bit
i tried in terminal and did 'ls > con.txt' and it created the file no problem, lol

but you're right, it's a feature of DOS

'con' is one of a number of reserved device names - since 1981, i just didn't bump into this for 45 years.

ok, digging deeper.

i can create con.txt in Windows Explorer, and edit the file. ...but then I get downstream weirdness like Terminal autocomplete can't see 'con.txt' - yikes.
And claude.ai reckons your filtering on con.txt is correct, "CON, and CON followed by any extension, is reserved" it claims MS docs say.

yep. ok . Windows is horrible and XY is in the clear.