Hi,
I have a strange problem:
Strange, because it seems to be easy, but somehow this doesn't work for me.
I would like to change the site logo to something else as the orange default HelpDesk Logo.
But somehow every time I try to change it I by the settings, I get this message:
If I go to the Site Assets and just switch the siteIcon.png file, it is changed for a while.
But after some hours/days it resets to the default one.
What am I doing wrong?
Hello Torsten! Please try these steps:
It works in the moment when I change the icon.
But immediately after I saved the changes and reload the page it is back to the old one.
This also happens if I clear my browser cache, then change it, save it, and clear again.
After I reload the old icon is back again 
Please try the workaround suggested in this discussion and let me know whether it helped. It seems that the hub association affected the possibility of changing the logo.
Hi Evgeniy,
It seems like this workaround is working.
I'll keep an eye on it for a few days and report to you if the success was persistent.
It's me again.
Unfortunately this was not a permanent solution, after a few days the logo switched back to the initial one.
I also recognized that the siteIcon.png is now on version 1266.0, which is more than 1 version per day we use this HelpDesk.
Any idea?
I tried to reproduce the issue but with almost no success. I associated a HelpDesk site with a hub site. Then, I changed the site logo and reload the page. The old logo came back. Then, I made some chaotic clicks in the left navigation menu (Tickets > Contacts > Home > Settings, to some points I navigated several times) and the new logo was restored. Then I cleared the browser cache and the new logo persisted. I don't know, perhaps, the default will be restored later but for now, it works as expected.
If you inspect the site logo on the page, you will see that its source is not a PNG file, but a response to the request:
https://e5evgevs.sharepoint.com/sites/TestHD/_api/siteiconmanager/getsitelogo?type='1'&hash=637782654098306559
So for me, it is not clear how exactly replacing the "siteIcon.png" file affects the displayed icon, perhaps, there are some cache issues on the SharePoint side. I would advise you to contact Microsoft support since it is purely the SharePoint functionality that should work in changing icons.
