You’re running unstable according to your profile, so breakage is expected at some point and you’re kindof expected to know how to deal with that.
If possible report the problem and your solution in the latest unstable announcement thread:
If you’re not prepared to do that, I recommend to switch branches to testing or stable and “fall back” to their current state:
$ sudo pacman-mirrors -aS stable
$ sudo pacman -Syyuu # note the double y and double u
If that solves the current problem, fine.
If not, please report back:
- What have you tried so far?
- Any log messages?
- (What were the latest package updates you got?)
edit: corrected pacman-mirrors command