ORA-15071: ASM disk "string" is already being dropped
Cause: An attempt was made to drop a disk from a diskgroup which was already in the process of being dropped from the diskgroup. Alternatively, an attempt was made to forcibly drop a disk from a diskgroup using the FORCE option which was already being forcibly dropped from the diskgroup.
Action: Check the ASM disk name and FORCE option as specified in the command.