Hi all, Currently, I found my WIN7 has a issue that "UMBus Enumerator" appears in Device Manager slowly sometimes. Please kindly refer to my attach files. umbus1.png is shown the beginning of bootup and wait 2~3 minutes the "UMBus Enumerator" will show up as shown in umbus2.png. I tried to use below command to trace what is going on here, but the recording time is too short for this case. xbootmgr -trace boot -traceFlags BASE+CSWITCH+DRIVERS+POWER -resultPath C:\TEMP Does any way to increase the recording time? Or any one met this issue before? Thanks.