"Failed to set plugin placeholders" message?
What worked for me, Go to your target Build Phases and on "Embedded App Extensions" check the "Copy only when installing" checkbox.
I had the same problem today. In my situation I had a different identifier in my original app than in the extension identifier "base". The extension has to have the same identifier as the original app plus something else.
E.g:
- Dummy App:
com.company.dummy-app - Dummy App Extension:
com.company.dummy-app.extensionName
After Xcode told me that, I changed my wrong names to look like above and then the problem occurred:The problem was, that I had "automatic manage signing" turned on but Xcode didn't recognize that I changed the identifier.
Solution:Just change the identifier again and check if "automatic manage signing" has created a new provisioning profile. Deleting derived data may also helps.
It took me a while to find the fix for this. First go to build phases click the X beside the embedded and delete it. This should fix the problem it is what worked for me.