Started having workstations with a MAJOR lag in booting. After seeing 6005/6006 Event IDs I applied a policy that enabled verbose GP Logging. After gathering a good amount of logs from affected machines, I started using Policy Reporter to view these logs and it became clear the time lag in processing began on a certain policy. Also saw that it happened when it got to the WMI filter. We had the same thing about the same time on a totally different forest, but on a policy that also has a windows 7 WMI filter. I removed it but we have other policies with WMI filters now the logs are showing them with these huge gaps in time after they start processing it... Based on the fact it is two separate forests with different policies etc. I am tending to thing there may have been a Windows update (or possibly another pushed out package) that is to blame- I have also seen some 5602 WMI event IDs and messages saying that it is restoring the WMI repository from a backup file.