Re: Several widgets disappear when .mo file installed
For all who are still having this issue. There was a bug fix 3 weeks ago that addressed this issue. See Changeset 1244. All widgets that come with BuddyPress were fixed with this revision.
If you are not running at least BuddyPress r1244, then you will still have issues.
Note: Custom widgets (3rd-party developed widgets), may or may not have implemented this bug fix. Therefore, if you are having translation issues with non-core BP widgets, you will need to contact the developer directly.