Tony.....
One Word WOW
So making a copy of your file.
Then backing up your file.
closing your file in FTM.
Then using FTM to Compact/Compress your file to 0.00%
does not help in your situation?
And first before the steps above have you
Cleaned up your PC's Hard disk a bit, say disk cleanup
and Disk defragmentation, a over worked Hard Disk Drive will sometime slow all the PC's programs down.
Is your PC being very chatty on your network or internet
which could bite into your resources?
Do you have more than one anti-virus/anti-spyware program running on your PC?
Whenever you write/modify a file, sometimes these program interrogate the file and the program that is being written/updated or modified in an attempt to protect your PC and data.
Is your PC running scheduled updates or scheduled scanning during the time you are working in FTM?
Any of these can effect the performance of programs and your PC.
Just some thoughts.
RSlack