Posey's Tips & Tricks
What To Do When the Remote Desktop Service Is Busy
If you receive an error, it may be caused by temporary resource strain, user logon storms or session limits -- often resolvable by waiting, but sometimes requiring deeper server diagnostics.
This morning, I tried establishing an RDP session with one of my Hyper-V servers and received a message stating that, "the task you are trying to do can't be completed because Remote Desktop Service is currently busy. Please try again in a few minutes. Other users should still be able to log on."
I use the Remote Desktop Services for remote server management almost daily and have done so for many years. This was the first time that I had ever seen this particular error, although I have been told that the error is somewhat common. The question is, what can you do about it?
My first bit of advice is that if you encounter this error, don't automatically assume that something has gone horribly wrong. Take the message at its word and try waiting for a few minutes and then attempt your connection again.
As previously mentioned, I received this message while trying to connect to one of my Hyper-V servers. With the summer heat beginning to arrive, some of my servers had been running a little bit hotter than I would like. Since I was going away for the weekend, I decided to power down a few machines before leaving, as a way of helping to keep my office cool (I work out of my home). This morning, I powered up my Hyper-V server and received the Remote Desktop Services is currently busy message when I tried to connect. Although I was admittedly a bit concerned about the message, I went downstairs, made a cup of coffee, and returned to my desk ten minutes later. This time, I was able to connect without any problems.
So in this case, it seems that the server really was busy, although I have no idea why I received the message this time, but had never encountered the error in the past. Even so, I couldn't help but wonder how to go about troubleshooting the problem if it isn't resolved by waiting.
Based on my research, there are a few different things that can cause the Remote Desktop Services to return an error stating that the service is busy. As an example, some have reported that the error can occur as a result of a logon storm. This problem mostly occurs in VDI environments, but it can theoretically also occur on other types of servers.
A logon storm is a phrase that refers to the activity occurring when numerous users all log in at the same time. Any time that a user logs in, the logon process results in CPU and memory usage. Storage and network traffic are also produced as a part of the logon process. Normally, the resource consumption associated with a user logon is hardly noticeable. However, if you have a large number of users who are all logging on at the same time, then those sessions could collectively cause a temporary resource shortage.
Another reason why the Remote Desktop Services might deny a logon is because the connectivity limit has been reached. Windows Server normally allows three management sessions (the console and two RDS sessions). In environments where more than two remote sessions are required, such as when users are establishing remote sessions with a server, Microsoft requires that you purchase a Remote Desktop Service Client Access License (RDS CAL) for each user or device. Connectivity problems can potentially occur if the server is not configured to allow a sufficient number of users to connect simultaneously.
Not surprisingly, another common cause for RDS Busy errors is that a server suffers from resource limitations. This is especially true with regard to high network latency, but a lack of CPU or memory resources could also conceivably cause problems. In fact, Microsoft recommends checking your server for memory issues and checking to see if any of the applications on that server contain memory leaks.
Of course, there are other things that can potentially cause the Remote Desktop Service to produce the Busy error. One potential cause is that an RDS session has become stuck. I will show you how to fix this error in a future column.
About the Author
Brien Posey is a 22-time Microsoft MVP with decades of IT experience. As a freelance writer, Posey has written thousands of articles and contributed to several dozen books on a wide variety of IT topics. Prior to going freelance, Posey was a CIO for a national chain of hospitals and health care facilities. He has also served as a network administrator for some of the country's largest insurance companies and for the Department of Defense at Fort Knox. In addition to his continued work in IT, Posey has spent the last several years actively training as a commercial scientist-astronaut candidate in preparation to fly on a mission to study polar mesospheric clouds from space. You can follow his spaceflight training on his Web site.