Saturday, June 14, 2008

How to fix Hyper-V error “Failed to add device Microsoft Synthetic Ethernet Port”

Hyper-V Beta, and RC0 worked great.  I recently upgraded to RC1, and in the process of both trying to move a VHD from another server and trying to create a new VM from scratch I repeated received the following error:

Failed to add device ‘Microsoft Synthetic Ethernet Port’

Here’s what I figured out: The Microsoft Forefront Client Security that was running on the host machine was interfering.  Once I excluded both .XML and .VHD files in Forefront, everything started working again.  That was an easy fix.

35 comments:

Anonymous said...

Shiz... FOREFRONT@(#*@#. Excluding root folder solved the problem.

Matt said...

I have the EXACT error, however I am NOT sure that I have ForeFront, how do I check? I just installed Server 2008 x64 bit and Hyper-V and downloaded to latest and greatest, and I am trying to create virtual server's and I can not get anything to work or start.

Thank you for this post, I am excited to try to get it to work.

Matt said...

AHH I have the problem with my AntiVirus software, TrendMicro OfficeScan, I don't have ForeFront, but I was looking in C:\*.* and program files and the registry, etc.

thank you!

Josh Robinson said...

Right - I am guessing that this is a potential problem with any anti-virus software. I just happened to have Forefront. Glad it helped you, that's why I posted it.

Anonymous said...

thanks everyone.
me too, meet with this problem.
and i exclude the *.vhd and *.xml,everything is ok.
and i also think that this is a potential problem with any anti-virus software.

Matthew Carter said...

I spoke with Trend Micro and they had me set an exclusion to Real Time Scan for the Snapshots folder, the Virtual Machine, and Hard Drives folders, if I did that, it worked. I can have Trend Micro's Corporate 8.0SP1 OfficeScan running and a new Virtual Machine can be initiated.

Anonymous said...

Excellent post. I had the same problem with Trend as well. Thanks guys.

Matt said...

Glad to have helped!

Anonymous said...

Just ran into this with a Hyper-V server at the office, excluded at the Forefront server vhd / xml files, and a reboot later, all is good.

Thank you very much!
JA

\w/alther said...

Trend Micro was the troublemaker here. Thnx for this useful post.

Anonymous said...

I run Trend Micro, and it was causing this problem. Glad I found this page/your posts as it resolved my problem. There really wasn't any notifications given that would have lead me to quickly discover that Trend Micro was causing the problem. thanks!

Dave Decker said...

Definitely Trend Micro, you fixed my problem right away. Thanks!

Matt said...

I can't take all the credit, if it wasn't for Josh's Stuff posting, I wouldn't even be here to try to help! Thak you Josh!

Anonymous said...

thank you so much Josh for this finding.. I was struggling for almost 5 hours to identify why could i not load even a new VM also despite reinstalling the Hyper-V Now i am safe back with my original VM.

tangoist said...

Another thanks, man! You've saved me some time! Great hint!

rudi said...

Same problem, just, i don't have any antivirus or security software installed!!
Got win server 2008 x64 with sp2 installed with SCVMM 2008. What now?

candrea71 said...

Thanks a lot! My OfficeScan was cousing the problem ;)

Anonymous said...

Thanks avg 8.5 resident sheild caused mine and excluding the Hyper-V folders worked.

Anonymous said...

Hi JOSH,, you are great.! i have been struggling on that problem the day used Hyper-V on Windows 2008 R2 and we're using Forefront AV.

But I have another error when I tried to add "Virtual COM port" I tried to add any IP, it say's "Error Applying COM Changes -- Failed to modify device "MICROSOFT SERIAL PORT"

I know this too much to ask.. just incase you know how to fix.. Please help..!!

TT said...

Thanks Guys...this was great and simple task, had to disable Trend but did not pick up that why it comlained about the 'Ethernet Adaptor' instead of something to do with the VM itself.....In any Antivirus .VHD files (at least) should be excluded anyway as a general rule.

PS: gfh whoever the f**K you are, dont post bullshit on these useful posts. Go spam some (l)users instead!

Josh Robinson said...

TT - Glad we were all able to help you. BTW - I hadn't realized that there was a spam comment on here from "gfh", was able to delete it.

Anonymous said...

Thanks a bunch. Great post!
I excluded the root folder for my virtual machines in Forefront and voila, everything worked. Thanks!

NITIN BADHWAR said...

Hi Josh

Thanks for the great help.
I was struggling since morning .Recently we have created Cluster Shared Volume on Host Machines, I was thinking SCV is giving some issue but ultimately found your post and resolved the issue.

Regards

Nitin

anuj said...

thanks
http://www.winservers.co.in

Georg Sollfrank said...

Yes, and even in Germany there are thankful people.

jon said...

cool

Anonymous said...

hello josh; ---- thx :) for an frustrated office scan user, this post saved a lot of trouble !!

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Ariel said...

Gracias!!! llevo 3 dias tratando de encontrar el error. Casi lloré cuando vi tu solucion

Viagra said...

Thank you for showing me how to fix this!

Anonymous said...

Uninstalled Trend completely, but still get this error, any suggestions??

azim tisekar said...


Logged on to the TrendMicro OfficeScan management console.
Networked Computers > Client Management > (note you can select a specific client computer here if you do not wish to exclude this directory from all desktops. Just browse for the desktop in question and then click Settigns button) Settings button > Real Time Scan Settings
Add directory exclusion. In my case I added in C:\ProgramData\Microsoft\Windows\Hyper-V\Virtual Machines.

thabang B Ndlovu said...

dude yu rock, had the same prob and also using trend micro but upon reading your post all my problems are over

Anonymous said...

What Matthew said work. I have TrendMicro and did the exclution and it works.

elangelx said...

thanks for the solution! ..