unable to open /var/db/sudo/ts/: Permission denied I'm having a really tough time trying to figure out what's going on with my High Sierra MBP. I've recently come across permissions issues, such as:

 $ sudo ls
 sudo: unable to open /var/db/sudo/ts/&lt;username&gt;: Permission denied


I'm then asked for the password and I'm able to operate as root, but I've never seen this error before. I've checked all the files/directories in /var/db/sudo/ts and they're all owned by root:wheel. My user is in the admin and staff groups -- this I have not changed. What would cause this? I came across this behavior when trying to update homebrew (noticed permission issues on directories my user owns in /private/tmp).

Similarly:

lrwxr-xr-x    1 &lt;username&gt;  admin    67 Oct 12 15:24 dtnoop_tracer.h
$ rm -f dtnoop_tracer.h
rm: dtnoop_tracer.h: Permission denied


Is my filesystem completely gone (or mounted read-only)?
That’s a very odd failure. I would probably boot to internet recovery and reinstall the os on top of what you have. If you have a backup, great and if not this isn’t a risky operation and something is certainly messed up with the permissions and sudo failures. 

Unless you have a very good idea why things are specifically broken, perhaps some scripts to change ownership or other sorts of administrative changes that you know were made to that system, it’s probably a lot faster to just get a get operating system and then fix any remaining problems every install doesn’t solve immediately.