fixed for me week ago
I have two intermittent issues that happen randomly to all my characters: Either I cannot change my talents at all or I get an issue learning some talent but the warning never informs me which talent I could not learn. I see this as a back-end issue, meaning something to do with Blizzard’s servers not updating or whatever. It seems especially prone to happen whenever there is peak numbers logged on, pretty much whenever I want to do dungeons and raids. I can sometimes get it to resolve and perform as advertised if I log out and log back in, but only sometimes. From my experience, running with no add-ons and regularly deleting the cache, this issue still occurs enough to convince me that there is a serious and fundamental coding flaw on the back-end of everything that this pre-patch has brought into the retail game.
Regardless of their attempt to fix this, it is still an issue. Hubby is having this problem on his ret pally and none of the above suggestions worked.
I boosted my priest yesterday and it had me choose Disc. Now I can’t spec holy or Shadow because it says Unable to learn talent. I temporarily fixed it by deleting and un deleting my character but as soon as I logged off and back on it went back to being bugged again.
I’m having the same issue. I boosted my Druid and was forced to take Balance spec, now when I switch to resto, I cannot apply my Starter Build or save any talents in Custom Builds. This issue is preventing me from being able to play Resto spec.
I am having the same exact issue as above. My Frost specialization is BROKEN. I can play other specs, but Frost does not work. After fiddling around I manage to apply a new talent tree build, but it didn’t actually take effect…there are zero Frost spells in my spellbook. All other specs work fine.
I still sometimes get Unable to learn talent error but I’ve also noticed that the talent window acts like it works but it actually doesn’t learn the spells. Like you can go to the spell book and the talents aren’t there. They are even greyed out on the action bar if you drag them onto it from the talent window.
I’m seeing the exact same behavior. Either the “Unable to learn talent” error or clicking apply makes a sound and visual effect as if it was successful. However checking my spell book, none of the abilities are added.
I also tried your trick of delete, then undelete the character. The same thing happened where it fixed the issue until I logged out. It was broken again when I logged in.
I hope they get this fixed before Dragonflight. I really don’t want to level up doing quests as Disc or Holy lol. That would be much slower.
This happened to my warrior after using a level boost to 60. It shows my class talent points as “-3” and my spec talent points as “-1” and any effort to redistribute them results in an “Unable to learn talent” error message. Any talent-related skills are grayed out on my bars, making the character mostly unplayable.
Maybe with another 189 posts we will be able to add this to the list of “known issues”.
Same issue here with Frost Mage.
It shows my class talent points as “-3” and my spec talent points as “-1” and any effort to redistribute them results in an “Unable to learn talent” error message.
Still broke and we are less than a week away 
I have same problem. I also tried deleting character and restoring, and that helped for like 3 hours. Then the problem came back, and now I got cooldown on restore character. Don’t seem like I will be able to play ret before launch 
https://us.forums.blizzard.com/en/wow/t/can’t-play-ret-after-boost/1414571
As if this is still happening. It seems worse now to. When I had first posted it was -1 and now its -3 to start and happening on boosted characters. I have been scared to adjust talents because of the fear of it coming back. This is terribly unacceptable.
Any update on this? I’ve had a ticket in and did as the GM suggested and that didn’t fix it and that was 2 days ago
What did gm say you try?
They logged onto my toon and tried it themselves and saw that it wasn’t working. They had me delete all my loadouts, restart and try again. Didn’t work
Ok, so i assume they at least know it’s a problem. I’ve given up all hope of playing before dragon flight launches
I can not apply my talents if i choose 2/2 burning blood as vengeance DH :S
I’m still getting the “Unable to learn talent.” message when I try to change from BM to any other spec. Can we get some type of response on this?