Another cause of this error is something outside of SAS locking the file. If you are storing a large permanent SAS data set on a cloud server such as DropBox and trying to read/write to it often, the cloud service may have the file locked while it is pushing it to the cloud. For example, I've run into this when running a bootstrap routine that was trying to save iterations to a permanent data set on a cloud server and also when trying to sequentially update a large permanent data set multiple times during a SAS program. The solution is to just read/write everything locally and not save to the cloud based server until the end of the program. ... View more