LR Classic v11.5 library filters stuck on 'Loading'

[NHPhoto4]

Hi,

 

Ive got an issue with the Library filter in LR classic (Win 10). If I try to sort images in a folder using the filter, it just says 'Loading' in all the available fields and doesn't complete the filter process. Anyone any ideas on how to fix this please?

[NHPhoto4]

UPDATE - I've now resolved this by using one of my recent backup catalogs. Something must have corrupted the previous Master catalog (Sorry I couldn't delete or edit previous post)