Form calculation not working.

[wallacealeco]

I am using a Count function 'Count(*)' in an unbound field in the form header of a continuous subform. All works well on my home PC but on transferring the database to the users PC, instead of showing the 'Count', the form sits there, blank field and showing 'Calculating... ' in the bottom left corner.
Both PC's using Office 2013 and windows 7. The recipients PC is on a small network. (About 15 PCs)
I have this problem with two forms on this database, one of which I can open as a stand alone form. Both problem forms are fed by queries.
Yours, hopefully

 

[wallacealeco]

Update: I have tried the database on other PCs on the network and the Count function works as expected! Going back the the original PC it now works on that as well! I have done nothing to this DB to cure it.
I had found, elsewhere on the net, someone mentioned Conditional formatting (which my Count fields have) had caused similar problems and once removed, the problem disappeared.
Thanks to anyone who may have been looking into this for me.