winsxs growing and taking up almost 50% of OS disk

server 2008r2 standard sp1 64 bit, 16 GB RAM, Intel xeon e3 v2 @3.10 GHz

40 GB OS partition, I have run disk clean up and ran all allowed DISM options on this unit, (only allows scanhealth) all others fail error 87,

have deleted and removed everything possible but winsxs continues to grow, down to 2GB left on OS partition, also cannot increase the partition. 

Any ideas to reduce this winsxs file size appreciated.

Thank you