I just had this issue and it turned out that a region server was up but not able to be reached for some reason. Rather than try and debug this, I restarted the region server and this fixed everything.
Sequence of events:
- Something happened to make the region server get into a bad state where it was reported up but unreachable
- Tried to disable a table while that region server was in the bad state (unbeknownst to me at the time). Got an RPC timeout error
- Tried to drop the table, got error "table is not enabled or disabled". HBase UI was reporting 'unknown' compaction status for that table
- Noticed a failed bulk load job that said it could not reach the specific region server
- Restarted region server
- HBase UI now reported table as 'none' for compaction, enables/disables/drops worked in shell