This is a message you may see generated at the console system (or, to be more precise, wherever system debug output is directed). It's always accompanied by a couple of strings which are parts of file names, labelled "Expected = " and "GOT =".
We can tell you specifically what this means but we can not tell you specifically what causes it. The reason there is a message being printed to the console is that it's something that was not expected to happen.
This happens when a file which has been modified is now being closed. When the file was opened, TSX remembered the name of the file in an in-memory data structure called a FIB (File Information Block).
When a modified file is closed, the operating system must update the directory entry with new information. To do this, it must read the directory entry, change it, and rewrite it.
At the time that the directory entry is read, the name in the directory entry is compared with the expected name from the FIB. If they don't match, the "File close comparison error" is generated. Note that since the directory entry appears to be for the wrong file, the directory entry is NOT UPDATED. This means that updates to the file ARE LOST.
If this happens, the most obvious suggestion is to boot to DOS and run SCANDISK. Usually this solves the problem.
In the interest of being comprehensive, we must report that we have encountered ONE SINGLE site when this problem turned out to be caused by hardware configuration. This site was plauged by dozens of these errors per day and their system was hence quite unusable. The problems had started suddenly, and the customer stated emphatically that no changes to the system had been made which correlated with the start of the problems.
After a couple of weeks of hand wringing, analyzing crash dumps, and stress, the customer finally admitted that the had, in fact, installed a "low end" Adaptec SCSI controller to control a tape drive he used under DOS; the model may have been 1520. This system ALSO had an Adaptec 1540 used by TSX, and it turned out that the two controllers were interfering with each other, corrupting data as it was being written to the hard drive!
In any case, while this is serious business, short of running SCANDISK, we simply do not have any suggestions as to what might cause this problem or what you can do about it.