I would suspect a network problem is more likely the cause of spinning wheel issues.
If you had a look at network traffic logs you would be surprised at just how 'chatty' ArchiCAD is - and if there is a delay in response due to a congested network or whatever, ArchiCAD will usually stall until it gets what it is looking for. License checking is particularly bad .. they make damn sure you will not get more than a couple of seconds if you don't have a license available.
I am currently in an office of 50 and the network is really being pushed. Frequent short periods of spinning wheel are so common people have stopped complaining about it .. its just what happens. Things have been tweaked and the situation improved a little but its still happens too often.
I've also had the same situation with a client (office of 15) whose network was well overdue for an upgrade (eg. large parts were not yet Gigabit Ethernet). Spinning wheel pretty much went hand in hand with an copy, save, send & receive ..... After upgrading the server and network infrastructure this problem was gone.
[Edit: I read the first post again - this is matches the most common problem these guys were having. FYI Copy & Save are two big license check flags, and then there is actually sending the file data over the network (25MB should not be a problem though).
Are you running off a network license key? If you are as a quick test to see if this problem is network based, try installing the network key onto one of the clients, disconnect from the network and work with the file on just that machine so all license checks are local. You should also make sure you are loading libraries locally, and that there is nothing in the file that will make AC try to make a network connection (hotlink module checks, titleblocks, etc). If everything is fine doing this then i would look at your network or server - are they up to the loads being put on them (hard to say without knowing how many people you have and what applications you are running). If the problem persists working locally then look at purging/rebuilding the file as others have suggested.
hope this helps
cheers,
Owen Sharp
Design Technology Manager
fjmt | francis-jones morehen thorp
iMac 27" i7 2.93Ghz | 32GB RAM | OS 10.10 | Since AC5