Jay and Conrad discovered today that MacOS install files downloaded from Apple have what amounts to an expiration date. And then they stop working.
Anybody run across this error?:
“This copy of the Install OS Yosemite application can’t be verified. It may have been corrupted or tampered with during downloading.”
Your copy isn’t corrupt; rather, it contains a security certificate that has expired. And it wouldn’t have to be Yosemite… ANY OS installer that was downloaded prior to February 14th, 2016, will contain this expired certificate.
Luckily, there are a couple of workarounds!
If this is a file you’ve downloaded previously from the App Store, it can be re-downloaded from the same. The new download will have an updated security certification that isn’t supposed to expire until something like 2023. Will we all be retired by then?
If all you have to work with is the old download, then the simplest thing is to roll back your computer’s date to any time before February 14th of 2016.