HTC One Messages app extremely slow, but just when I text one person! My friend (who texts me a lot of pictures of his kids) sent me a barrage of pictures and one video. Ever since then, texting him is excruciatingly slow. These things happen:


Just getting our text thread to open takes much longer.
When typing, some words get stuck and I have to wait until the word is completed.
When I do get the text written and hit send, the message disappears for a little while, then it appears, but as not sent yet, and then  after 30 seconds, finally sends. 


Texting all other people is just as quick as it ever was.

I'm wondering if it's because I've got so many pictures in the thread? Can't think of anything else.

I'm deleting some pictures, to see if it helps, and I think I might try clearing the app's cache, but I'm not sure what that does.
Might be a small bug because it is specific to only one contact. Hoping you've saved all the stuff you want from that thread, delete the thread/whole conversation. If you don't mind delete the contact also by writing his number somewhere. Now start fresh again by creating the contact again and see what happens. Comment.