Metal door frame; the screwholes holding the strike plates are stripped out. What to do?
If you have sufficient space behind the material in which the hole has stripped, you may be able to make use of a rivnut. It's a threaded insert which matches the required threads (machine screw, not sheet metal or wood screw) and requires a larger hole to be drilled. Once inserted, the tool compresses the back side in the same manner as a pop-rivet or blind rivet and secures the threaded portion for return to normal use.



The image above shows a metric version available from Amazon.com, but SAE sizes are also common enough. Some tools for installation can be expensive, or as simple as a wedge with a bolt to apply the proper force.



The above, also from Amazon.com is obviously not a wedge type, but is not the hundred dollar version.