I'm suddenly having a very strange problem that I've never encountered before. I'm almost 60 levels into this character and the problem started after completing the CW questline for the Stormcloaks, although I'm not sure if that's relevant.
What is happening is that when my character is moving around the gameworld, all of a sudden most functions seem to just disappear. The only key on the keyboard that does anything is the Esc key, which still brings up the menu but I can only access the Save/Load menu, and the Settings menu. Everything else is greyed out and clicking on it with the pointer does nothing. I can't bring up the map, I can't bring up the journal, I can't bring up anything with the Tab, Q, I or P keys, and all onscreen options for interacting with things disappear - I don't see the onscreen text for 'talk' or 'open' or 'take' etc. when I have the pointer over NPCs or doors or playable items and hitting 'R' doesn't do anything, I don't bring my weapons or equipped spells up for combat. If I am in Sneak mode I immediately come out of it without warning and without pressing the appropriate key. Also the crosshair, which is set to be invisible in most circumstances via iHUD, immediately reappears but as I said I don't get any option to interact with things when it's hovering over them.
I would suspect iHUD because of the crosshair thing, but I've used it for ages and never had any problems and I don't know how that would explain all the other functions disappearing as well. I am using Civil War Overhaul and it's my first time playing through this far with that one, and I did have some notable glitches during the final battle in Solitude that made me replay that bit several times, but on the final runthrough everything seemed to go fine - we finished the battle, all the usual scenes were played out, etc. However it was almost immediately after finishing the CW that I started having this problem... I found out soon afterward that I had large bounties in a couple of holds and fast traveled to each of them to pay them off and when I was released from jail in those cities and tried to walk away was when I think it started happening. I reloaded a couple of times and tried to pay off the bounties with console commands but that didn't work.
I managed to reload a save from just after the end of the CW, to before I had one of the hold bounties, and successfully paid off the one I did have at that time with console commands. Then I just avoided getting the second one. I thought maybe this glitch had something to do with my having been sent to jail when I first tried to get rid of the bounties, it's been ages since I had that happen and I thought maybe the game disables certain functions while you are doing time and it just didn't re-enable them properly after I got out. But as noted I managed to avoid any jail time, went straight back to Windhelm from Solitude via the ferry, and wandered around there for a day or so in-game doing some bartering and preparing for what I was going to do next. Had no problems while in the city or on the docks or out by the stables.
Then I left Windhelm and set off south through the wilderness, and it's happening again. What's odd is that I can get about as far south as Steamcrag Camp before it happens, and after trying various routes on the road and off, and checking the area in the CK, it seems like what is triggering this is when I cross from one section of navmesh into another. You know how when you pull up a non-interior part of the world and look at the navmesh you can see where one section of it borders up against another? Yeah, it appears to be happening when I cross one of those borders.
I did completely remove CWO and reloaded and took the same path south from Windhelm and it still happened, so I don't know that CWO is causing the problem either... and it's such a weird, unexpected thing that I don't know what to think or where to look, especially since it does seem like crossing from one navmesh to another is the trigger. I should probably note that moving from cell to cell via loading screen, either by passing through a load door or with fast travel, doesn't seem to trigger it.
Any help or suggestions would be greatly appreciated!