I have had very bad experiences with chkdsk and my maps. Fat32 does have an individual file size limitation of 2GB. When chkdsk.exe is run it will see an error and break the file down to under 2GB. This makes the over 2gb map image useless. The copy I made of my 8GB SDHC card with the latest Europe maps, JCV's, Topos etc is useless. The ability to back up my SDHC cards is critical as they are very time consuming or impossible to reconstruct in the future. Track data, trip favorites, etc are easily list forever. I have all my maps saved on an external drive which is formatted as Fat32 and had been deleting the smaller RAR folders as I thought they were passe. If I convert the file format to NTSC that may correct the file size limit, but my 2TB of data may not be safe. NTSC drives are also a major PITA to recover if there is a failure.