Problems downloading a tree from Ancestry

I am still trying to get used to RM8 and trying out some of the features. This morning I had 2 attempts at downloading a tree from Ancestry (I have editing writes to the tree).
1st attempt, seemed to freeze, I didn’t see the progress bar page until I decided to quit. Then RM 8 froze completely.
2nd attempt, I got the progress bar, but I got an error saying it couldn’t connect to Ancestry at 58% download of media… I ok’d the error message but RM8 was stuck again and wouldn’t let me out of the task… again had to use taskmanager to close RM8

Is the problem due to the size of tree? c5000 people
I can open the tree in RM8, the media downloaded, isn’t attached so I don’t know what 48% didn’t make it unless I manually attach the media… RM8 says I have to be signed into Ancestry even though I have ticked the box to say logged in. If I do that, then attaching the media will duplicate on the online tree.

Thankfully, this is only testing on my part, I already have the tree in RM7 offline.

The tree in question belongs to my cousin which I created for her, I don’t want to have to start repairing the Ancestry tree.