can't change sheet name on tab

[LisaAnn]

have used excel forever and have not encountered this problem. have tried to
rename a tab at the bottom of the sheet and keep getting error message saying
i've used an invalid name/character. i haven't used anything that is
disallowed... just the word "Staff" or "Department" no other symbols or
numbers, etc. i checked sheet protection... okay. it also will not close the
program without fixing this problem.

 

[LisaAnn]

i think i have the problem solved... although i would like to know why? i
found that the person named the whole spreadsheet with [ brackets ] as a part
of the name. as soon as i took those out, the tabs could be renamed. if
anyone can share how that worked i'd like to know! Thanks