I have several datasets that I have maintained and added to over many years, going all the way back to the DOS version of TMG. I'm currently using version 9.04. About once each year I export a GEDCOM of each (current) dataset and upload it to an on-line genealogy service. Recently, exporting one of the datasets produced a severely truncated output, even though the processing of the export took a normal/reasonable amount of time, and messages from TMG show the right number of people (2035) and families (795). Some of the output seems okay, but much of the dataset does not make it into the GEDCOM output file. When viewed in TMG, the dataset looks perfectly normal, even looking at the families where the cutoff in the GEDCOM seems to have occurred. I get no on-screen error messages directly from TMG during export, and I do get the final note that says the GEDCOM has been created. There are sometimes error messages in the log file, but I can't interpret them. I have tried re-indexing the dataset, and that doesn't help. I last produced a valid GEDCOM from this dataset in Version 8 (or possibly 7--I didn't notice at first that there were missing families in the output). The GEDCOM output seems to be of a different size each time I try it, but always much smaller than it should be. There are no apparent changes or problems in the display of the dataset within TMG v9. The last line of output of the GEDCOM file is a "1 FAMS @F10@", rather than the normal source information lines and final "TRLR".
I haven't found any problems in exporting a GEDCOM from ver. 9 with any of my other datasets. Is there a validation tool for checking datasets, one that might check for non-obvious errors? Does anyone have any other suggestions on exporting the GEDCOM?