Time machine does not recognize external hard drive.

schmidtp wrote:

I have a Lacie Share Porsche design hard drive, which I used as a backup drive for my old macbook pro 2015. I never had any troubles, but that laptop crashed a while ago. I'm now trying to backup my current laptop, a macbook pro 2011, to the same drive, but it is not recognized as a backup possibility in Time Machine. It shows up in the finder, I can access all files, but it is nowhere to be seen when I try to select a backup drive in Time Machine. Screenshots below.

Any help would be great!

https://discussions.apple.com/content/attachment/91947e35-e03b-492f-b4c8-79ddc52bb427

https://discussions.apple.com/content/attachment/f52f5dff-f306-4554-ac72-4fe886ffca67

Hold the Option key and click on the TM icon in the upper right menu bar>Browse Other Backup Disk

Back up your Mac with Time Machine - Apple Support

If Time Machine on your Mac can't find your backup disk ...