Thanks will try that. Further testing suggests that that might not have been the issue though. I get the feeling that the companion was too close to his horse, although the others were pretty close too. I'll have to test it further though.
Some things from my last playing session:
What does the "stop tracking" option do on the companion tracking dialog? Doesn't seem to do anything. I would have thought it would remove all companions from the list or something. There is no mention in the readme.
Sometimes when they go to mount they get stuck, I think it's just a game bug. As I mentioned in the readme just giving their horse a nudge will get them to mount.
Stop Tracking stops the tracking quest disabling the quest arrow and stopping the script from processing. Not a big deal as the script only processes every 5 seconds, but if you're not tracking you have the option to stop the quest.
I notice that accessing the inventory of a companion through your Share option unlocks any locked items (thankfully not causing a crash of course, as you explained). Is there any way to keep items locked and still access their inventory, or does your add-remove-add script on all their items make this impossible? I ask since I would hardly use the locking ability then, since I access their inventory fairly frequently and don't want to then go through each item again and re-lock it.
No, all items are removed when you look at their inventory. No way around that I'm afraid, FO3 has a much better companion share feature, but it lacks some of the nice messagebox features that OBSE gives, so I can't even do the inventory there like I can here.
Is the CompanionHorseSupportFIX esp still necessary for CM Partners? If so, will merging it with CompanionMaster do any harm?
It is essential for the horse riding, resurrection, and location orders to work properly. I wouldn't merge it in Companion Master, you are better off merging it into one of the CM Partners esps.
EDIT: Is there any harm in having a companion in two places in the companion list? Just curious. And lastly
Is there any point to having the horses themselves on the companion list?
You can have them in two places if you want, but I don't know why you would do that. You can remove them with the remove function, and it will only remove the one entry you select, not both, if you have them in two places.
Only reason to have horses in the list is if you want to be able to track them. I made it so that horses don't respond to the group commands even if they are in the list so you can dismount, give a group follow order, and that will reset the companions follow distances closer then when riding horses, but leave the horses where they are.