That was an issue a few years ago and then had an update from some other site to fix. I highly recommend that you change another program since both of the programs from Sierra no longer work in Windows XP or 7 even though it previously worked in XP. I got error messages about tree.exe that even a reinstall did not cure and now have years of files locked up in UDS files. I had the latest Generations software so that was not the issue. Convert your UDS and scrap using Generations is my advice. I beleive a prgogram called the Master Genealogist will open a UDS file.