[KarlG]

Let's say an epub has a file called Cover.xhtml.

I wish to rename it to cover.xhtml, but Sigil tells me that the name is already in use.

I get the same error message when trying to change the case of an image name.
e.g. change CH01FIG01.jpg to ch01fig01.jpg

As a workaround, I can rename the file something like Covera.xhtml and then rename again to cover.xhtml, but it would be nice to avoid this additional step.

I understand the current behaviour is by design, to allow for Windows being case-insensitive, but I'm pretty sure even on Windows it's possible to change the case of a file but keep the same name.