Time Machine stopped backing up external HD

[LaurieL]

Hi y'all, I've been backing up my Macbook Air and external drive (1TB drive - about 3/4s full) to a 2 TB drive via Time Machine every week or two or three.

I just realized it stopped backing up the external drive in May 2017. Does anyone have an idea what went wrong? Or a suggestion for how to get Time Machine to start updating the external drive again when it backs up?

Thank you.

 

[BrianBaughn]

Did your external somehow get on the "Exclude" list (System Preferences>Time Machine>Options…)? If so, remove it. If not, try adding it then removing it. If that doesn't work, let us know.

Also, what brand of external drive is it?

 

[LaurieL]

Did your external somehow get on the "Exclude" list (System Preferences>Time Machine>Options…)? If so, remove it. If not, try adding it then removing it. If that doesn't work, let us know.

Also, what brand of external drive is it?

[doublepost=1516300254][/doublepost]
Just realized the problem. The Toshiba was new in June, it never got backed up once I switched to it from my other external. I misread the exclude list - it was there! thank you.