I guess that is one way of testing if your backup is good,
but if you discover the problem before you close Excel, you would
be safer opening your .xlb file without exiting Excel. The .xlb is
saved each time Excel is closed whether it needed to be changed or not.
It is by default a hidden extension. So make sure you do not have file
extensions hidden. My page on this is
http://www.mvps.org/dmcritchie/excel/toolbars.htm
http://www.mvps.org/dmcritchie/excel/backup.htm
If you do physically restore your .xlb file, make sure that Excel is down, and I mean
really check in the Task Manager (Processes). Make sure you restore the
file to the same exact location. Fixing your toolbar buttons, and menus is
not fun. I have a page on it that might help but Bill Manville who hangs out in
the excel.links newsgroup is working on a utility which you can get if you do
have the problem. (better to make sure you don't cause problems than trying
to fix them).