I have been using Photoshop Elements 10 on my MacBook for years with no problems until recently when some things stopped working. I recovered my license number and downloaded the file, but when I tried to install it I got this message:-

"The app’s authorization has been revoked

There may be a problem with this app. Although the app was signed by an identified developer, the certificate for the app has been revoked, and it cannot be opened.

Check with the Mac App Store or the software developer to see whether there is an updated version of this app.

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I purchased this software and have been quite happy with it. I do not want to pay for an upgrade or a newer version and see no reason why I should have to. Is there any way to re-install this app?