Have you been suffered from Mac error 1309? Of course this is very serious issue and needs to be resolved as the earliest. Usually you can see this error code while copying large file from Mac to external drive. This would cause various problem as you can't transfer favorite items where you want. Typically mac error 1309 appear when the destination volume is not compatible file system. Apart from user limited permission might be the cause of this problem. Now coming into resolving the error and to do that one can check the size of file. Besides verifying disk permission through disk utility and reformatting the volume into Mac supported file system as HFS, HFS+ would be helpful in resolving mac error 1309. But in case there is data loss occur, moving into data recovery is must required that can be done either backup or by taking help of third party solution. If the backup is present then it is fine. Otherwise Mac Data Recovery Software is taken into your consideration without confusion. It is the best and effective third party tool which enables you to retrieve any kind of lost data within just span of moment. Hope this way you would be able to fix mac error 1309.