Obscure Skype for Business desktop sharing issue

A colleague of mine reported an issue with Skype for Business where he was unable to either share his screen (or application or PowerPoint presentation), nor could others share their screens with him.

From the user’s side, clicking on the Present button allowed him to toggle what he wanted to share, which would appear to work – the border indicated “connecting” while the recipient(s) waited for the presentation to begin. After 30-40 seconds, the presentation error (…”the invitation has expired”) and time out.

If you encounter this issue, you can try the following registry hack, which worked for me:

  1. Open Regedit as an administrator
  2. Navigate to:
  3. Add the following DWORD and value:
    MaxUserPort=0000x3a98 (15000)
  4. Reboot for the changes to take effect.

You can find more information about MaxUserPort and other TCP/IP registry settings here. This issue seems to be newly introduced with Windows 10 version 1809.

16 thoughts on “Obscure Skype for Business desktop sharing issue”

  1. Thanks – this fix worked for me! Please note there is a typo in your hex value which should be 3A98 / 15000. You have it down as A98.

    Thanks again – life saver!

      1. I´m not in doubt but it won´t work on my side and i don´t know why…
        I set the Reg settings / Rebooted some times and stay on the last release of Office 365 (Office MSO (16.0.11328.20156) 32-bit)
        Maybe a problem with the Graphics Driver??

        1. Hi Philip,

          I’m sorry you didn’t find my suggestions helpful. Please understand the intent of this blog is record issues I encountered and to share what worked for me. I provide this information freely in the hope that it might lead someone, somewhere to the answers they’re looking for. That said, I can’t guarantee that what worked for me will work for you.

          This is because I have no way of establishing that you are in-fact experiencing the same issue I was, nor do I have any way of replicating or even verifying the circumstances that have created the issue(s) you’re experiencing.

          I cannot provide support through comments on my blog. My recommendation would be to contact Microsoft support or seek out other avenues of assistance (e.g. Microsoft Support, forums etc.).

          Thanks in advance for understanding!

  2. Hi,

    I am also facing issues in Skype for Business 2016. We have a Sync Server in the environment that is used to enable users so that they can use Skype.
    I am able to do Screen Sharing with some users but with some users, the Screen Sharing does not work.

    We have tried many options but the issue is still unresolved.

    Looking forward to hear from you.


    1. Hi Vikram,

      Thank you for reaching out to me! I’m sorry to hear that you’re having issues, but as I explained Philip above, I cannot provide technical support via the comments section of my blog. The purpose of this blog is document issues I’ve encountered in which:

      1. The information I needed was difficult for me to come by
      2. Scattered across several websites
      3. Buried deep in some forum
      4. …and/or phrased in an unclear or misleading way

      The information on this site is provided as is, and I make no guarantees whatsoever that what worked for me will work for you. These posts are intended to teach and demonstrate possible solutions to specific problems which I couldn’t easily find the answer to. I can’t troubleshoot your issue for you anymore than I would expect you to troubleshoot issues in my environment for me.

      My recommendation would be to leverage your MSP for assistance by logging into https://admin.microsoft.com, clicking on ‘Support’ > ‘New service request’. Sorry I couldn’t be of more assistance, but try to understand I’m just one person and don’t have the time or resources to provide free tech support :).

  3. Hi,

    Thank you for posting this solution. It worked for one of my user on SfB 2016 experience similar issue on Windows 10 1809.

    Many thanks

  4. Thank you so mush for this amazing article.

    Desktop and program sharing are fine, I got a problem with present PowerPoint Files.

    Any suggestions pleas?

    1. Hi Mohammed,

      I’m glad to hear that you liked the article, and sorry to hear that it didn’t address the issue you’re facing with PowerPoint files.

      You haven’t stated what specific problem(s) you’re facing so I can’t give you a specific suggestion, however, here’s how I’d go about troubleshooting this:

    2. – Establish if it’s specific to certain users or if it’s affecting everyone
    3. – If only certain users are affected, determine how they differ from ones that aren’t
    4. – Determine if it’s specific to certain users or if it’s affecting everyone
    5. – Was this always a problem or did it occur recently? What changed?
    6. – Is there a specific error message they’re getting? Any related events in the event log?
    7. – Have you tried patching/rebooting?
    8. Those are some general steps I’d take to determine the issue.

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