Sounds like a volatile function such as offset or indirect, or a large range is being referenced, or could be conditional formatting related or lots of possibilities.
I’d save a copy and delete one sheet at a time to narrow it down to which is the problem sheet.
Also pressing END HOME on each sheet and see where the cursor goes to see if you have a very large sheet
Depending on you excel version you may have the Inquire addin which can help clear excess formats.
Wyn
[MVP]
