Created bootable external hard drive that had existing files, now I can't access any of the old files.

[shitzerblitzer]

I created a bootable partition on an external hard drive to install Catalina on a new ssd for my 2015 MacBook Pro, now I can't access any of the existing files on the external hard drive. In disc utility it still shows that the hard drive is full with all my files, but I can only access the bootable software used for installing Catalina.

 

[chabig]

I think you’ll need to show your Disk Utility window. Without that it will be hard to help.

Please show all devices and make sure we can see your partitions.

 

[shitzerblitzer]

 

[sbuntin]

what was the folder structure previously on the external?
Might help to run OmniDiskSweeper to get a visual of what's on the data volume.