BertelS

As I said, the browser cache, along with any other caches involved, were purged between tests. I even changed browsers. I could reliably replicate the err by switching Yoast 3.0.1 on and off various times (with cleaned caches in between …)

Downgraded to 2.3.5 , no more problems. “Add Media” works with 2.3.5

All caches etc cleaned between tests ….