I just tried copying a 7GB file to the HDR via a samba mount. The copied file was identical to the original (verified by SHA1 signatures).
When copying from the HDR, are you allowing sufficient time for it to be auto-decrypted? If not it will not be playable on the external device.
The files on the HDR are already decrypted and shrunk (auto-decrypt and auto-shrink) and files less than 2GB transfer OK. The PC is running 32bit Windows 7. The 2GB limitation happens in both directions but with differing results. If I try to copy a 2.6GB .ts file from the PC to the HDR using Windows drag and drop, I get an error message saying there is insufficient space on the HDR. If I do a "properties" on the HDR drive from Windows it shows the full size of the drive and says that there is 364GB out of 447GB free. If I transfer a file larger than 2GB from the HDR to the PC using Windows drag and drop, the copy completes without any errors and the resulting .ts files are playable on the PC but the files on the HDR become corrupted and are no longer playable on the HDR (in some cases they aren't even recognised by the HDR). Copying them back to the HDR from the PC using FTP results in a playable file back on the HDR so they are not corrupted during the transfer. Transferring the files using FTP (Filezilla) works OK regardless of file size.
I have 2 HDRs both with the latest levels of the custom firmware (auto update) and both exhibit the same behaviour.
On further investigation it looks as if the problem may lie with the interaction between the Windows 7 code and Samba on the HDR as I can copy files larger than 2GB from the PC to the HDR using Teracopy on the PC instead of the Windows 7 code without the insufficient space message (right-click and drag the files I want to copy or move from the PC to the HDR and select Teracopy to do the move). The resulting file on the HDR is playable but interestingly Teracopy reports that the file copy failed even though it didn't.
When I get the time I'll try to work through and document all the different scenarios.
One further thing to mention is that I also have a Foxsat-HDR with custom firmware and I don't have any of these problems between the PC and this box using Samba shares.
I must say that I'm surprised that no-one else appears to be having these problems and after 30 years in IT I'm prepared to accept that this is a problem limited to my setup.
For the moment I'll stick to using FTP.