RPC Server Unavailable

Category: Windows

After helping a friend clean up a nasty spyware infestation, we had one remaining problem. Windows would say RPC Server is Unavailable when starting up, and also later when trying to print or install new software. Some other things just didn't work, like copy and pasting text, and right-click menus. Here's how I solved the problem and got the RPC server running again...

What's a Remote Procedure Call (RPC)?

A little background... RPC is an acronym for Remote Procedure Call, and typically is used to allow a program running on one computer to access services on another networked computer. I say "typically" because Microsoft added some of it's own extensions to the standard RPC protocol and deeply intertwined RPC into the inter-process communication of Windows operating system components. So if RPC stops working, lots of other Windows features will fail as well.

In this case, I didn't know if the "RPC Server Unavailable" problem was caused by the malware we had removed, by one of the anti-virus or anti-spyware tools, or something else. No matter, it was broken and my friend wanted me to fix it. I did a bit of poking around on the Web, and found lots of information on RPC. There are some viruses and spyware that try to exploit an RPC server software bug, but we had already applied the fix for that. Another article said that if the RPC server is not running, one can go to Control Panel / Performance and Maintenance / Administrative Tools / Services then double click on the Remote Procedure Call entry and either start the server, or set it to start automatically on system startup.
RPC Server Unavailable

I tried that, but the Remote Procedure Call entry did not appear in the Services list. There was an entry for Remote Procedure Call Locator, but that's a different service, not related to this problem. When I looked on another computer that was working properly, the RPC entry did show up in the Services list. So I clicked on Properties and learned that the name Windows assigned to this service was RPCSS. This bit of information proved to be an important clue that helped me solve the "RPC Server Unavailable" problem.

Blame the Registry

Windows RegistryI figured that since RPC was missing from the Services list, it probably had something to do with the Windows Registry. The Windows Registry is a hideously complex ball of string, rubber bands, duct tape and bailing wire that's supposed to keep track of Windows system settings, your hardware configuration, user preferences, file associations, system policies, and installed software. It was supposed to be an improvement on the collection of simple text-based INI files that stored Windows configuration settings, but too many pocket protectors got involved in the design and the result was an over-engineered, over-complicated mess that makes Windows much more fragile and harder for users to maintain. I've seen so many cases where the Windows Registry got mucked up by malware or a system crash, that I decided to blame the Registry and ask questions later.

Since I had one working machine and one broken machine, I thought that I might find the problem by comparing Registry entries on the two systems, looking for missing or incorrect keys related to the RPC Server. But where to start? I did find a Microsoft KnowledgeBase article that mentioned a Registry key called HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Rpc, but that key looked fine on the problem machine when I examined it with REGEDIT.

Hack the Registry

So I poked around on my own machine until I found HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\RpcSs (remember RPCSS from above?) and noted that this Registry key was missing from the problem machine. I knew from years of thrashing around in the Registry that both HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run and HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services have something to do with the applications and services that are automatically run at system startup time, so this seemed promising.

I exported the RpcSs key from my Registry (using REGEDIT's File/Export feature) and imported it to the other machine (with REGEDIT's File/Import), thinking there was NO way this would solve the problem, but it was worth a shot in the dark. Wonder of wonders, I rebooted and everything was back to normal. The RPC Server showed up in the Services list just like I had hoped, and it was running!

I should add the caveat that mucking about in your Windows Registry can be dangerous, if you're not careful about what you add, delete or modify. So make a backup of your Registry before you do so. The easiest way to backup your Registry is to create a Restore Point using System Restore. See my article on Using System Restore for more help with that.

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Most recent comments on "RPC Server Unavailable"

(See all 104 comments for this article.)

Posted by:

12 Mar 2010

Hello Mr. Bob,
i need to ask you something reacently itried to install some printer on frend compyuter and i got message tht the rpc server is unavaleble i tried your solutions andididn't secsided canyou tell me what istheproblem andcanit be hardwere problem not softvere

Posted by:

12 Mar 2010

After a conficker virus infection and repair efforts my entire CURRENTCONTROLSET key is missing. My system fails on boot at a WINSRV not found error, but this is due to the RPC not functioning. RPC could not be started from the services manager. If copying the missing key from my laptop does not work it seems a good time to migrate from Windows XP to Windows 7. Thanks for sharing the fruits of your labor!

Posted by:

17 Mar 2010

Had a problem like this. A user got infected with a anti-virus malware (Windows XP). The infection added a dependency to the rpc service. When the dependency (a bad program) was removed, RPC no longer worked. Just used regedit to remove the DependentOnService entry under the rpcss service entry, rebooted and rpc worked again (along with all the other services dependent on it).

Posted by:

Mike Meier
28 Apr 2010

Thanks for the article. Between it and the comments it helps understand this problem better. But, in my case, the RPC error seems to be associated with COM+. A program I wrote talks to another program that is on the same computer, and it all worked fine for months, then the RPC service error again! In past instances we found problems with the network and solved that, then with power-save features on the PC and the network card itself. Turned these off and we're fine. Then the problem hit again last night. Any ideas on RPC and it's effect on COM+? I do understand that RPC can effect numerous other services on a PC, but have not seen any specific mention of COM. Thanks.

Posted by:

17 May 2010

I can't synchronize items to my mp3 player, because it says my rpc server is unavailable, this didn't work. Any help?!?

Posted by:

25 May 2010

This actually worked! Nasty spyware!! Thanks :)

Posted by:

shanil jain
07 Jun 2010




Posted by:

10 Jul 2010

The article is no help to those of us that don't have inter-connected machines, from which to import the registry entry from the working machine.

Posted by:

05 Aug 2010

Hi, I just uninstalled nic card driver, rebooted, problem solved. Not sure if malware. Still searching.

Posted by:

02 Nov 2010

please help, i had read your article but not solution, my problem with sharing folder if i want sharing folder the message " ..... RPC Server Unavailable". I have reformat my pc but the message still like this, so would you help me

Posted by:

08 Dec 2010

Thanks Bob! After looking at my Ipconfig info more closely, it told me that there was an RPC problem. When I read this article I checked my services an sure enough, my RPC Locator was not running and was set to start manually. I turned on the RPC and problem solved. Thanks for the info. Bobby

Posted by:

24 Dec 2010

Thanks for the article.

Posted by:

31 Mar 2011

Thanks for this. Helped me allot. :)

Posted by:

23 Apr 2011

Can actually start rpcss using the DOS command: net start rpcss.

Ex: Start > Run > net start rpcss

Posted by:

21 Sep 2011

Dear Bob,

I used LENOVO G530 with 32bit OS (vista Ultimate), 984 MB RAM size, pentium (R) Dual CPU local disk size of more 260G. My system suddenly started acting strange. I cannot serve pictures from the internet, can't save adobe reader files anymore from the internet, so many sofwares are not launching again, my printer is practically not responding and even mozilla fire fox software I use for browsing and some other softwares I use for music among other things.

I often get the repply that RPC Server Unavailable when I try to save pictures from the internet or do some other things. I have gone through your article on "RPC Server Unavailable" but I didn't quite get it because I am not a system engineer.

Please kindly help with the breakdown I need to take to resolve this issue. It is really affecing me and making me seek.

I look forward to your response soonest. Thank you very much.




Posted by:

22 Mar 2012

Hi Bob,
thanks a lot, you've helped me solve my problem. In my case, it was enough to run the "Control Panel / Performance and Maintenance / Administrative Tools / Services" path and tick "start service".

Cheers and greetings!

Posted by:

01 May 2012

Thanks. I didn't understand anything from the technical terms you wrote. It's already for someone who is knowledgable enough to solve this problem. So thanks for nothing.

Posted by:

13 Jan 2013

This actually worked for me, after trying to resolve the problem for the last 24 hrs. THANK YOU SO MUCH!

Posted by:

28 Jul 2014

Rather than exporting registry from one computer, which admittedly is likely not identical in its software load nor history, would it not be easier to simply re-register the service?

c:\Windows\System32>regsvr32 rpcss.dll

Posted by:

Terry Hollett
21 Apr 2016

I just had to help someone getting this error message when trying to print to a network shared printer. The solution in this case turned out to be simply stopping the Print Spooler service and restarting it.

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