I have suddenly come up against this issue with my share extension, both on the simulator and when I run it on a device.
I run the extension from the scheme and I get the dialogue "Choose an app to run", I choose Photos and then when I go to the photos app and select to share I get the following message in the debug panel:
my_extension_Bundle_identifier Waiting to Attach
This was working fine a while back, but suddenly I got this issue. Any ideas
Fixed this issue by deleting the Share Extension Scheme and then AutoCreating it. Additionally, the main storyboard reference in my Share Extension plist was wrong.