an antivirus could be blocking the downloads, which used to happen to me.
Is there a way to find other accounts with characters that are not allowed currently?
This also occurs in 1.11.2.
EDIT: Yes it is an error.
[08:26:33] [Client thread/ERROR]: Couldn't open link: Failed to open file:/D:/Users/MyName/AppData/Roaming/.minecraft/screenshots/2017-05-21_08.26.30.png. Error message: A device attached to the system is not functioning.
[08:26:34] [Client thread/ERROR]: Couldn't open link: Failed to open file:/D:/Users/MyName/AppData/Roaming/.minecraft/screenshots/2017-05-21_08.26.30.png. Error message: A device attached to the system is not functioning.
Probably not working because your .minecraft is in the D:/ drive. Works fine with my brother and his .minecraft is in the C:/ drive.
If you are on a server, it is probably lag.
Make sure the crafting tables and chests are not in spawn claim.