You will see this message currently on the exp branch where we are trying to get feedback if this fix actually fixes the problem ==== Just a stab in the dark (for me the error appears to be gone on the public branch when I check on my PC) Steam just did the weekly Tuesday night maintenance can anyone here restart their steam client & start the game in the public branch (v1.7.9) & see if the exception still appears for you at the main menu or any message in the console like this "ArgumentException: An item with the same key has already been added. Key:"
In Exp branch after the 1.8 II update the problem was there still as in the screenshot you provided. Today morning 07:30 (GMT+3) I restarted steam loaded the game and it is gone on Exp. 1.8 II . PS : By the way why I tried to open the screenshot from your thumbnail to new full page I get this
on 1.7.9 linked workshop items still there: the error messages in empyrion are gone, but the problem for linked steam entries still exists just shifted it seems. i went through my workshop blueprints and everything starting with "thu..." and further down the alphabet is still marked as unlinked now. before this was more random/mixed from what i remember, now it is everything starting with "thu..." until "z....." without exceptions. (+my old 5ish unlinked blueprints are still affected, but again these had the issue for a long time and probably have something other broken on their files itself, so i disregarded these, but some come before "thu.."). edit: steam subscriptions seem fine the issue with subscribed blueprints for me seems to be gone now. at least i now see blueprints i did not before when the error messages showed up. (i reduced the subscribed items before when i discovered the issue, but even when the error was there it did not fix the problem. since i know you can only have a certain amount that shows, but while the error was active the amount was definitly under the cap and subscribed blueprints did not show, now the subscribed blueprints show properly.)
I wonder if the duplicate keys are actually duplicated BPs or different BPs that happen to share the same ID? Possibly the latter because "duplicate" is only referring to the key, not the actual BPs. If different BPs is the case, it would be nice to see in the logs both BPs that share the key. Maybe something like: Workshop element '221TorusDevdb' (1429812159) received again. Key shared with 'DonutsForever' - skipped
I found an easy fix. (which worked for me) Go into Empyrion in steam and validate the game files. I got all my blueprints back