You know.a partition with FAT32 file system could NOT be put into a file which is larger than 4GB.i dont know you meant to move what file or whether it is over or under 4GB. ok .if its not .i think there is a writting-limit with the drive you were trring to move files to .just simply turn the writting-limit off.
If it is a result of file system.use a “partition wizard” to convert within seconds
I wish it helps