Last Monday, we started getting multiple reports from MacBook users experiencing an issue with their Citrix Workspace app for Mac. At first the issue wasn’t very clear to use, because everybody reported it slightly different, but soon we noticed the common thread was the resolution. Affected users somehow got a very high resolution in their Citrix session, while their local screen resolution was normal. The Citrix session didn’t seem to adopt the local screen resolution.

I wasn’t able to reproduce the issue myself, so I contacted an affected user. He had done some analyses himself and discovered a curious phenomenon. If you would ran the Citrix Workspace App setup again all seemed to be fine. A Citrix session would adopt the local screen resolution upon connection. Soon as you rebooted the MacBook, the problem suddenly returned. Reinstalling the Citrix Workspace app again made the issue disappear.

We compared the Citrix Workspace App version we were both using and noticed a small difference. The affected user was running version 22.04.0.44, I was running 22.04.0.25. By the end of the day I upgraded my Citrix Workspace App to version 22.04.0.44 and rebooted my MacBook hoping I would also be able to reproduce the issue. And indeed I had the issue myself 🙂

At first I was just a little misled. I thought the issue was caused by the latest version 22.04.04.44. I took a look at the release notes and immediately noticed the section “Support for high DPI monitors [Technical preview]”.

Citrix Workspace app for Mac is now compatible with high DPI monitors with resolution greater than 4K. On desktop sessions, apps, text, images, and other graphical elements appear in a size that can be viewed comfortably on these high-resolution monitors.

Although this was an option that you had to activate manually, it had to do with screen resolutions. It appeared that this feature was inadvertently activated with the upgrade to 22.04.0.44. If this feature was indeed causing the problem, we could test that by manually disabling it. To disable this feature, run the following command in macOS terminal:

defaults write com.citrix.receiver.nomas EnableHighDPI -bool NO

And indeed soon as we disabled the feature all seemed fine again! We opened a support case with Citrix telling them something went wrong after updating our Citrix Workspace app for Mac to the latest version. After the support engineer had looked at our case and made internal inquiries, he came up with a remarkable response. The issue hadn’t been caused by the upgrade, but by Citrix. We heard that the product team unintentionally had turned on the DPI Scaling feature via Launch Darkly during the weekend.

After the problem was discovered the default setting for this tech preview was quickly disabled again. The engineering team will need to do more testing on the feature before making it enabled by default. So in the end we learned the issue was also present in 22.04.0.25 but wasn’t activated until a reboot of the MacBook and the settings from LaunchDarkly were applied.

If you are still experiencing the problem yourself, now that Citrix has disabled the option again, just reboot your MacBook and your Citrix Workspace App should work as expected