VIrtual disk is not rebuilding. Stuck at 99%.

Hi all!

We've faced a strange problem with AX4-5i system.

After disk fault in the RAID5 disk pool the global hot spare disk had began rebuilding but progreess stucked at 99%. After waiting for a 1 day without any progress we decided to replace faulted disk and after that to pull out hotspare disk. After hotspare disk had been pulled out disk pool began rebuilding with the replaced disk and progress stucked at 99% again. And now 2 days later it's still here.

What we can do in this situation?