No, that flag (MoveFlags.AcrossVolumes, which corresponds to MOVEFILE_COPY_ALLOWED and has the integer value of 2) is present on the two-argument version of MoveFile. Are you using the three-argument version and specifying MoveFlags.None (0) instead? That's certainly not going to work.
I admit I haven't tested the inter-volume move, but according to MSDN it should work. You can check the source if you like; that isn't a recent change.
I admit I haven't tested the inter-volume move, but according to MSDN it should work. You can check the source if you like; that isn't a recent change.