Remote Desktop Connection Manager Distorted Display

Remote Desktop Connection Manager (RDCMan) is a very popular remote administration tool with Microsoft admins.  RDCMan allows us to minimise the number of open windows on the local machine, when connecting to multiple remote systems.  At the time of writing, the latest version is 2.7 which can be downloaded here

On my Windows 10 1511 laptop, some of my Azure VMs were not correctly rendering the display.  In the below screenshots you can see that the screen is not painted correctly and that there are many artefacts in the output.

Paint It Black


In this example, the screen is black, with patches of grey and other pixelated silliness.  If I wanted pixels, I’d be playing Minecraft….


More Pixels Than Minecraft

If you see this issue, some troubleshooting steps that you may try (probably unsuccessfully) are:

  • Logging off the remote server
  • Restarting remote server
  • Restarting local machine


It is most likely an issue with the locally cached bitmaps.  In order to clear the bitmap cache, close RDCMan and remove the cache files out of this folder on your local machine (NOT the remote server).

C:\Users\%UserName%\AppData\Local\Microsoft\Terminal Server Client\Cache


Bitmap caching places commonly used bitmaps, such as the one that displays the Start button, in a file on the client computer. This improves performance by minimizing the amount of display information that must be passed over a connection.

The option for bitmap caching is not really exposed in the RDCMan interface, but you can see it below in the standard RDP client.

Windows 10 RDP Client



Comments (17)

  1. Menko says:

    Cool, works! Thanks. I was done with the RDP Minecraft-edition yes 😉

  2. TechNet says there is a new blog called “Exchange Services Not Starting on Windows Server 2012 Due to Network Location Profile”
    but when you click it you get “not found”

    1. Unfortunately yes – its due to this:

      That post was published out automatically from the old platform, and is not visible on this one yet. It should go out tomorrow morning.

      I have already contacted the blog support team, as I don’t want the old platform to repeat this.

      Sorry for the false post!


  3. Martin says:

    Thanks, this was just what I needed. First time it happened to me I ended reinstalling my pc (which of course solved the problem). Now the problem returned, and I found your blog, yeah.
    Do you by any chance have an idea as to why I can’t get any of my Win2012 R2 servers to “fit to screen” in RDCman using Win10 1511. In Win7 this was never a problem. If I select “scale to fit” in settings I get a window that is to small and unchecked I get a window with sliders.

    1. Try setting display scaling to 100%, and reduce the resolution to help with readability.

      My native resolution on this laptop is 2900 * something. Currently have it set to 1920 * 1080.


  4. Sathish says:

    Thanks a lot . It helped me 🙂

    1. Dan says:

      Worked for me. Thank You 🙂

  5. Brakhmaputra says:

    Thanks a lot! Very smart fix)

  6. Tony says:

    Hi Roderick,

    Thanks for this. I ran into this issue yesterday. I’m using Windows 10, and my system crashed while logged into a client machine using RDC. On restore everything appeared to be ok, but when going back in to the client system the screen would display random pixels only, preventing me from working. IT support could not help, and after numerous searches found your solution, tried it and the system is back to normal.

    Many Thanks!

  7. TJ says:

    “The option for bitmap caching is not really exposed in the RDCMan interface”

    But is there some way to turn it off in RDCMan, globally?

  8. Naveed says:

    Worked like a charm , thanks man

  9. magster says:

    I know it is off-topic, and you seem to not work on this software, but maybe you can get the word to the right people…

    When using smart card, the “Username hint” field of logon credentials dialog should be populated according to the username that is saved in the profile of the connection in the same way as the username field is set on password logon with NLA.

  10. Jumbobazman says:

    Thanks – the clearing of the cache worked for me – it was getting very annoying managing multiple desktops through plain old MSTSC.

    Only started after a Win10 upgrade

  11. Ben says:

    Genius, thanks!

  12. Morquecho says:

    Thanks…I use RDCMan alot and my new 2016 Server had this issue….

  13. Selva Kumar says:

    Thanks ,Its working

Skip to main content