Are you using special characters in resource names? Look in the resource
view and see if you have many, many duplicate resource names. I've seen this
happen when special characters are used in resource names. The duplicates
cause the file to become quite large as the resource names replicate each
time you save the project.
Is this an old file? Sometimes I have seen the project file begin to bloat.
The fix has always been to simply copy the data into a new file.
(Indicative to the MS Access Compact and Repair Option, not available to
MSP), but in corruption or migration the system tables were reset and the
file size restored to normal
