How do I play on Solo offline and then change to also play in a friends oline server.
I have done it a few times first playing my moded (10) solo off line version, then I login to the server version, but first I turn off all the Mods not in his server. I do that but end up with my solo version having been damaged ? 
Are you making sure you turn all the mods back on before logging back in to your solo game?
The modding experience in UE5 is a pain in the ass. I have 2 servers active; they have a decent amount of overlap in mods, but some are unique to each experience. To change I have to go through a huge dance and ritual before I can get on the server properly; if I don’t, it becomes a maddening experience of reloading and reloading and getting error messages and getting dropped before the server could load and more reloading.
I’ve noticed that the modlist.txt doesn’t fully update when making changes. If I enable/disable mods and order them to the proper load order, when I then reload the game, I have the correctly enabled mods, but not in the correct order. So then I have to reorder them and restart again. The fact that you have to load the game before you can even edit your mods is such a giant annoyance.
I know servers will yell/prevent you from joining if your mod list is wrong, but I don’t think the same protections exist with single player. There should, at the very least, be a warning that you have x missing mods and y added mods compared to the most recent save that asks you to confirm you want to load or cancel to fix.
Conan Exiles mod management looks like it should functionally behave the same as Rimworld but is a really poorly developed version.
Mods are certainly more difficult than they were - I don’t believe this is actually due to the upgrade itself, but rather a result of Funcom’s launcher being broken for this feature and Funcom having little impetus to fix it, since they are no longer responsible for developing the game (essentially, I suspect there is a little bit of a ‘territorial p*ssing contest’ going on - Inflexion can’t fix the launcher, because it’s Funcom’s launcher, but Funcom doesn’t ‘care’ because it only affects a game that is no longer ‘their problem’…).
(An additional factor is that with the upgrade, we lost access to CodeMage’s excellent BUGLE launcher, which did so much of a better job than the base Funcom one ever did, especially for swapping modlists around.)
Possible reasons aside, there is a way (at least for singleplayer, but probably also for servers) that we can make this process easier for ourselves:
Navigate to the ‘Mods’ folder (by default - C:\Program Files (x86)\Steam\steamapps\common\Conan Exiles\ConanSandbox\Mods)
There should be a file called ‘Modlist.txt’ (unless you have no mods currently in use - this will work better if you get a modlist set up correctly for one of the destinations that you intend to play).
If all of the places that you wish to play have the same mods in the same order, and just have some additional ones, then it is possible to ‘comment out’ the unwanted ones by adding a semi-colon at the start of that line - then reactivate them by changing the textfile when you want to go to the other list.
Assuming that the lists are too different for this to work - create another folder on your desktop and copy modlist.txt into that folder (and add something to the filename to make it easier to identify - eg the server name or character name).
Then go through the song and dance of setting up the second modlist correctly - and create a copy of that modlist in the same folder (and again, add to the name).
Then, once you have two modlists that each feature the correct mods for those games, in the correct order - manually swap those files in and out of the ‘mods’ folder as needed (remembering to change the name back to ‘modlist.txt’ when they are ‘active’).
(In fact, you could probably just keep them all in the ‘mods’ folder, since the game will only look for ‘modlist.txt’ and will therefore ignore ‘bobserver modlist.txt’, until you rename it to be the active one.)
This way, at least you only need to exit the game once, swap the file, and restart the game, rather than having to go through the extra steps the game currently enforces.
Yeah, I actually went ahead and did exactly this for the current server I am on. Haven’t logged back in to the other to need to swap back but once I do, I’ll do the same thing. It’s just such a half-assed system that it irritates me, compounded by the fact that I did indeed use BUGLE prior to the UE5 update and didn’t have to deal with it at all previously, and that’s when it worked slightly better to how it works now.
Like I mentioned, if it worked similar to Rimworld’s, it’d be fine. Can access workshop and subscribe to mods while the game is open. Can save modlists and swap them out as needed (game reloads when you do this). Game will pop up an alert to let you know if you are trying to load into something (including multiplayer if you use the MP mod) where the mods are different than they should be. Rimworld’s mod handling is exactly what Conan’s should be, down to the supporting different versions of the game since you can easily roll back to prior patches.
What I do is define the mods for my game. Reboot. If I want to play my solo game I just play. When I want to enter an online game I get a warning that they do not match or that it does not use a mod. I give you the option to download and subscribe and then connect. That will make the game restart and try to connect… it will give an error… I cancel it and I go to play online and I give the server I wanted to enter to connect. When I want to play my local game I restart or start conan and just play. (If something sounds wrong it is because it is a Spanish translation)