I’m having the same issues that several people are having when updating a mod, uploading a new mod, or downloading a new mod–and as someone who loves making maps and tuning packs, this is a major turn-off.
The “finalizing download” or “finalizing update” comes after the download/update bar hits 100%. Upon hitting 100% it says one of those two phrases and never changes.
This is happening when I try to make updates to my current mods and/or when I try to upload a brand new mod. If I host a custom game with a mod that I haven’t made any changes to today (one that was made prior to today), then I have no issues whatsoever–the game loads like normal and the other players load the mod without issue.