When attempting to download 1.12 pre-release 4, the launcher would download the .jar file without problem, would load several .lang files then hang. If we waiting long enough, the launcher would crash. Re-attempting allowed us to get further in the download process. After multiple times (about two dozen), we were finally able to complete the download and play the game. Of the four Windows 7 machines we were playing on, this only happened to one of them.
If a crash report is needed, I can add one this weekend. This may be a duplicate, but I did not find a report that mentioned a hang at this part of the process.
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No, she does not have ByteFence.

Anyway, this is technical support, not a bug.
Does MCL-5546 describe your issue?