Either something has changed in a relationship or calculation, or as is more frequently the case, the content of the field is longer than the defined width of the field can accommodate. An example would be if you have a field that "just fits" 3.25% but all of a sudden the calculation returns 3.257% and there isn't room for the extra digit, you'll see "?".
Thank you for the reply. Additional Info: The table has three scripts to create the records. (about 70000 currently, last 300 readable). One on File Open that sets fields Timestamp, Get User Name, Get Account name, and text "log-in". Same on close but with text "log-out". No calculation or relationship involved. Also, if I do a find that would return 2 records, I get a display of 2 lines of "?" question marks. Seems to indicate there is data still there.
There's a bug in FileMaker that may be at fault.
For More Information see: Phantom Record, damaged file message, Recover can't detect a problem
This is one of many acknowledged bugs that can be found in the Known Bug List here in the Report an Issue section of the forum.
It can also be downloaded as a database file from: http://www.4shared.com/file/8orL8apk/FMP_Bugs.html