55MB database. Transaction log is currently 696GB. App will let that grow forever, which is undesirable, for obvious reasons - and the backups were silently broken for ~6 months, so it wasn't getting backed up either. DB is in an always-on group, so I've been trying to avoid putting it into simple mode, but no combination of backup w. truncate, shrink, etc seems to be releasing that space. Trying a double backup/shrink right now (every time I try I lose ~25G). Given the size of the DB, I'd really like to get that 600G back - and now the backups are fixed so the log backups should run in a sane fashion too. What am I missing? Is there no choice but to take the app down, take it out of the always on group, nuke it from all but one node, simple mode / backup / shrink, and then readd to the group? /not a DBA. Just forced to fix this.