Fix Common Problems reports "Default docker appdata location is not a cache-only share".

The solution points me to Shares, appdata.

I cannot set "included disk(s)" to empty- empty allows every disk.

I can exclude every disk.

Use cache disk is "Yes".

I am new to UnRaid and fairly sure I am missing something really basic... but have no idea what.

Cache- yes is not cache only. There are 4 possible settings for Use cache. 

 

Since you have been using the wrong setting, it will likely require a few steps to get your set up working more efficiently. 

 

Go to Tools-diagnostics and attach the complete Diagnostics zip file to your NEXT post.