WMF5 Performance when dot sourcing

I noticed some performance issues dot sourcing scripts in modules, taking up to a minute to load in all of the files.

I tried to investigate and isolate using procmon on a handful of PCs running WMF5.
The scripts ran instantly on PCS using WMF4, as well as on the WMF5 pcs after uninstalling WMF5.

To test further, I created a file named test.ps1 with the following contents.

$t = "hello"

The procmon capture did not account for the time, unless you include the profiling events, which I believe are irrelevant.

PS C:\temp2> Measure-Command { .\test.ps1 }

Days              : 0
Hours             : 0
Minutes           : 0
Seconds           : 3
Milliseconds      : 833
Ticks             : 38337812
TotalDays         : 4.43724675925926E-05
TotalHours        : 0.00106493922222222
TotalMinutes      : 0.0638963533333333
TotalSeconds      : 3.8337812
TotalMilliseconds : 3833.7812

PS C:\temp2> $PSVersionTable

Name                           Value
----                           -----
PSVersion                      5.0.10586.117
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0...}
BuildVersion                   10.0.10586.117
CLRVersion                     4.0.30319.42000
WSManStackVersion              3.0
PSRemotingProtocolVersion      2.3

On average it takes 3-5 seconds to load a dot sourced a file.

Any ideas on what is causing my performance hit, or how I could further troubleshoot this?

Hi Michael!

If you do end up discovering what was causing this, might be worth following up here and your stackoverflow post in case someone else runs into the same issue. Very curious to hear what was causing this.


Here is the SO post for anyone interested: StackOverflow Post

Still waiting to pinpoint the exact cause. I created a test computer and noticed performance was fine on Windows 7.
Moving the computer into a different OU causes the problem. It looks like it’s down to a GPO, or ePO policy causing the conflict.

I notice this line in the McAfee Access log each time I try to run a dot sourced ps1.

Would be blocked by Access Protection rule (rule is currently not enforced) NT AUTHORITY\SYSTEM C:\WINDOWS\SYSTEM32\SVCHOST.EXE C:\Windows\System32\wbem\WmiPrvSE.exe Anti-virus Maximum Protection:Prevent svchost executing non-Windows executables Action blocked : Read