Windows Remote Desktop: Disconnected Because of a Protocol Error

Windows has a built-in software called Remote Desktop Connection (RDC). This software allows us to open our PC from any place, using a laptop or even a mobile phone ​[1]​. In rare cases, we can’t access our PC, and an error shows up:

Because of a protocol error, this session will be disconnected. Please try connecting to the remote computer 

Reasons

Commonly, this error is due to low memory (RAM) on either the client computer (i.e., the computer in front of you) or the remote server (i.e., the computer you want to connect to). Some applications may hog resources in either one of the computers. Thus, the RDC is not getting enough RAM to start the connection.

RDC requires at least 1024 MB or 1 GB of free memory (RAM) to start the connection ​[2]​. Accordingly, there are two solutions you can try. First, reduce the connection quality. Second, close unnecessary applications.

Solutions to protocol error

Before trying any solutions below, try logging in with a different username (if available) ​[3]​. Although it rarely succeeds, it is worth trying.

Solution 1: quality reduction

On the client computer, open the Remote Desktop Connection. If you can not find any options (as in Fig 1), click ▼ show options. Then, do the following ​[4]​:

1. Go to the Display tab, then:
   • under Display configuration, set a smaller resolution, and
   • disable Use all my monitors for the remote session option.
   • Under Colors, select the lower color depth (e.g., 15 bit).
2. Go to the Experience tab, then:
   • select the lower connection speed, and
   • disable all of the visual quality (e.g., Desktop composition and Visual styles).
   • If necessary, also disable the Persistent bitmap caching.
3. [optional] Go to the Local Resources tab, then:
   • under Remote audio, click Settings..., and
   • disable the audio by selecting Do not play and Do not record.

Solution 2: close unnecessary applications

On the client computer, open the Task Manager. Under the Performance tab, check the available Memory.

The client computer may have insufficient available memory. Therefore, try closing unnecessary applications (e.g., web browsers and Microsoft Office) until you have at least 1024 MB of available memory. Although, it would be better if you could free up to around 1.5 – 2 GB of memory.

Meanwhile, attempting to close unnecessary applications in the remote server is challenging. Unless, You have a person that is physically close to the remote server ​[5]​. Some people talk about CMD instructions to restart the computer remotely. However, I would not recommend it for two reasons. First, I haven’t found any instructions that work. Second, we don’t know whether any essential applications may still be running and haven’t been saved.

References