Rockstar Games rolled out its Grand Theft Auto Online update for Grand Theft Auto 5 earlier today, but you might want to back up your save file before diving in, as some users are reporting lost progress after installing a required patch.

A Joystiq tipster writes in with word that their single-player campaign save file was erased following patch installation, ending a playthrough at around 70 percent completion. NeoGAF and Rockstar Support users confirm similar glitches, reporting missing weapons, unresponsive character switching, and an inability to progress in story mode.

While many players have installed the update without issue, others report hard-lock freezes and character creation difficulties within the game's GTA Online component, and for some, the single-player mode is effectively unplayable. Rockstar has posted a list of known multiplayer issues, but has not yet commented on reported single-player glitches.

"The GTAV Title Update to enable Grand Theft Auto Online access has been rolling out this morning on PSN and Xbox LIVE across territories worldwide," Rockstar explained in a comment here. "As mentioned last week, you should expect that there will be some technical teething issues in the early days of a new online experience especially one as massive as GTA Online - you can stay apprised at the Rockstar Support site here. Thank you all for your patience, understanding and support!"