Not able to update from 10.8.5 to OS X Mavericks I'm currently trying to update my mid 2009 Macbook Pro to Mac OS X Mavericks. I've downloaded the file from App Store several times the but every time when the Install progress reaches about "1 second left" a message pops up saying that the download might be corrupt or that the program can't be verified.

I already tried the following things:


Check HDD (also at boot with Cmd + R)
Check that apps are compatible to work with Mavericks
Checked HDD size (about 40 GB left)
Downloaded from different internet accesses
Made all offered updates mentioned in App Store


My drive is FileVault encrypted.

It's enough to drive one to despair.
Try changing the date to current date in terminal. You can follow Jonathan Mohar's advice.