Running Windows 11: Is there still no fix for the annoying upgrade advert every time I launch a NIK app ?
If I remember right, these go away after 30 days.
Ensure PL is not open.
Ensure any other applications that can call NIK (e.g. Photoshop, Affinity Photo) are closed.
In Windows Explorer, enable the checkbox to allow you to see hidden files and folders then navigate to:
C:\ProgramData\DxO\Nik Collection
In there you’ll find a file called NikCollection.cfg
Open that file with Notepad.
Look for the section “Checkforupdate” and set the key name value to “2632040964”
Look for the section “Startup” and set the key name value to “0”
Save the file.
That should make the nag screen go away.
PS if you ever have to reinstall or you ever update NIK then these tweaks will be lost so make a note of them somewhere.
<group name="Checkforupdate">
<key name="LastCheck" type="string" value="2632040964"/>
</group>
<group name="Startup">
<key name="ShowAEP2PromoScreen" type="bool" value="0"/>
</group>
thank you 
I’m intrigued … What does that key represent ? - and, how did you work that out ?!
…seems to work with macOS too. Edit the following file:
/Library/Preferences/DxO/Nik\ Collection\ 6/NikCollection6.cfg
If we look at the file, we can see the timestamp, which starts with “0” at whatever point in the past. Take that number and make it greater to set “Last Check” to somewhere in the future. I set the timestamp to 1999999999 and the nag was gone.
Please note that any search for updates resets the timestamp.
@platypus has explained what this key does. As for how I worked it out, this question comes up regularly so you just have to search the forum to rediscover the solution
Ah, yes, that makes sense - Thanks for the helpful response, Mr P … 
I see lots of fancy hacks but can’t you just change the setting in the notification to only show on updates? Its what i do and I only ever get the dialog once on an update. Its a drop down withthe default being to show it every time you start, but you can change it to monthly or only on updates etc.
You can do that but if you choose not to update then the nag to update appears every time (well, for at least 30 days, which feels like forever) you start PL.
Yes, that’s fine if you’re running one of the recent versions of Nik Collection - but, for older versions it nags every time the app is invoked … which is quite annoying.