I have a document library that is well over 5,000 items. I need to update the document library permissions, but I'm unable to do that, whenever I try and break inheritence it gives me the warning
'The attempted operation is prohibited because it exceeds the list view threshold enforced by the administrator.'
I have also tried via the CSOM.
Surely Microsoft hasn't made it impossible to change permission once a doc library is over 5,000 files?