Question: Cannot download a new clean copy of OS X Mavericks
I have an old MacBook Pro that I would like to either give away or sell. I have low-level formatted the internal hard drive. I created an external hard drive with a clean installer on OS X Mavericks. However, when I go to install it on my internal hard drive, I get the following message: "This copy of OS X Mavericks application can't be verified. It may have been corrupted or tampered with during downloading. Delete this copy of the application, and go to the Purchases page of the Mac App Store to download a new copy." I have not deleted yet it but I did go to my purchases and the OS X Mavericks installation is greyed out. I cannot get it to reload. I own this, I purchased it years ago - the App Store will not allow me to download my own software. Any thought on how I can overide this? Thanks.
Mac Pro, macOS Sierra (10.12.2), 48 GB 1333 MHz DDR23 FB