Messages won't open on Macbook - Solution found.

I FOUND A SOLUTION!  i hope it works for you, could work for everybody or nobody but it fixed my issue entirely!

and before reading any further i implore you to share this somehow if you can because Apple Forums don't let me reply to the other users that never found their solution. the thread gets locked after it doesn't see any replies after a couple of months.

anyways, Messages would immediately crash and a notification would pop up saying "Messages quit unexpectedly, ignore/report/reopen" i tried everything with an Apple Support tech, all the way up to backup computer and erase hard disk, which made me pretty much give up.  until i accidentally fixed my problem with a workaround!

Try this:  take a *SCREENSHOT*.... after capturing a screenshot, click the screenshot thumbnail that appears on the bottom right of the screen after taking the screenshot (quick!  because the little thumbnail will go away after a few seconds), then when the window opens up with an enlarged view of the screenshot, click the “Share” button in that window (looks like a square with an arrow pointing up).  then when the small window opens up that has a list of recently texted faces/icons which indicate “text this screenshot to this person”, click one of the people.  BOOM.  for me messages suddenly opened up, with the screenshot ready to be sent to that person.   and it’s opened up just fine since then!  

it would seem that this method is a workaround for whatever the glitch/bug is that makes it crash.  

the only thing that i’m not sure it needs, is to have messages sync turned off iCloud.  i turned sync off just to try it, and it was still off when i did this trick.  i don’t think it’s the operating system because had updated to the latest OS and it still crashed right away.  

i think it was just a glitch in loading Messages in the last state you left it in, but this screenshot trick takes you STRAIGHT to the person you’re trying to text and doesn’t attempt to load up the last text you sent or open messages in the state you left it in before closing the app last.  which leads me to believe that if this trick didn’t work the first time, you should try it again but try sending it to a different person.  

i hope this helps, get this post up-voted so people can see it! my attempts to respond to other people with this problem have all failed, the threads are "locked".