Please help at finish install

Traceback (most recent call last):
File “/opt/rockstor/src/rockstor/rest_framework_custom/”, line 41, in _handle_exception
File “/opt/rockstor/src/rockstor/storageadmin/views/”, line 320, in post
return self._update_disk_state()
File “/opt/rockstor/eggs/Django-1.8.16-py2.7.egg/django/utils/”, line 145, in inner
return func(*args, **kwargs)
File “/opt/rockstor/src/rockstor/storageadmin/views/”, line 68, in _update_disk_state
disks = scan_disks(settings.MIN_DISK_SIZE)
File “/opt/rockstor/src/rockstor/system/”, line 126, in scan_disks
base_root_disk = root_disk()
File “/opt/rockstor/src/rockstor/system/”, line 875, in root_disk
raise NonBTRFSRootException(msg)
NonBTRFSRootException: ‘root filesystem is not BTRFS. During Rockstor installation, you must select BTRFS instead of LVM and other options for root filesystem. Please re-install Rockstor properly.’