I was onsite last week loading a client's PowerPoint on to one of our show laptops, when I was suddenly confronted by a new and frightening error message I had never seen before. It went a little something like this: "PowerPoint was unable to display some of the text, images, or objects as slides in the file (name) because they have become corrupt. Affected slides have been replaced by blank slides in the presentation and it is not possible to recover lost information. To ensure that the file can be opened in previous versions of PowerPoint, use the Save As command and save the file with the same name or a new name."
Naturally, we were a little concerned. When clicking through the error, the presentation opened, but was missing almost all of the graphics and all the colors were wrong. We opened it on the client's laptop, and it worked fine. We re-copied it onto a flash drive and loaded it again on ours with the same scary error message. We loaded it on to a secondary show laptop, and again, the message. The presentation loaded fine on the client's laptop, and on another personal (non-company) laptop.
I did a little research, and discovered that the day before Microsoft had pushed a PowerPoint "security update", and reports were starting to trickle in of the mysterious error. The update is called "Microsoft Windows Security Update for Powerpoint (KB2464588)", and the problem can be reversed by uninstalling the update.
There is also a Hotfix that supposedly fixes the problem: http://support.microsoft.com/kb/2543241
**IMPORTANT NOTE: If you do as the warning message says and "Save As", the new file will be permanently missing the "corrupt" images. If you do not save, the original PPT will load just fine once the update has been removed/repaired.