Bugs are frustrating, but please realize that sometimes they happen despite best efforts. Lets keep small annoyances like this perspective and not say they're "ruining customer trust." Save that claim for situations like selling your data or generally being evil and untrustworthy.
I hope you reached out to the development team with a constructive bug report to help them track down your issue.
Bugs, bad upgrade paths, adding "features" while losing polish, etc. are all great ways to lose trust.
Bugs/etc are a great way to lose my business, but not a way to lose my trust.
(what you're saying isn't lost on me, I just reserve "trust" for the situation I alluded to -- an important distinction given online privacy concerns/etc)
I installed the update, and after it just said would you like to link your account or something I clicked yes, and was brought straight to my inbox, no need to reenter passwords or anything (seamless). Sounds like his experience was due to Dropbox now supporting business accounts yet.
When Apple releases a new version of iOS or OS X there are always plenty of bugs compared to the previous versions which have had a year to work out all the bugs. Doesn't make me trust them any less.
If a person (like the author) doesn't want the newest product versions they should simply disable auto-update and update manually after a certain amount of time.