?Microsoft PowerPoint is a reliable application for a presenter to make effective and compelling presentations. But, sometimes you may face issues while opening a PowerPoint presentation. The problems could range from unreadable text to startup issues to several randomly generated error messages. You can face such issues with presentations created with PowerPoint 2002, 2003 and 2007. In worst scenarios, the above-mentioned issues lead to damaged slides and data inaccessibility. Though, you can try some repair strategies as provided by Microsoft, the chances of recovering the data successfully are not much bright. This also depends on the severity of damage to a presentation. To overcome such issues, you must consider using professional PowerPoint recovery software. Consider a scenario, wherein, you try to open a presentation (sent by an e-mail or saved on a USB) in PowerPoint 2002, 2003, or PowerPoint 2007, and instead receive the following error: PowerPoint 2002 and 2003 "PowerPoint can't read pathfile_name.ppt." PowerPoint 2007 "PowerPoint found unreadable content in Presentation.pptx. Do you want to recover the contects of this presentation? If you trust the source of this presentation, click Yes." To get the unique number associated with the error message by pressing Ctrl+Shift+I. The following number will appear along with the error: 400645 Cause The root cause of the abrupt behavior and error message is PowerPoint presentation corruption. A PowerPoint presentation can get damaged in various instances including application malfunction, abrupt system shutdown, virus attacks, power fluctuations and more. Irrespective of the causes behind corruption, you can recover PowerPoint presentation on your own. The details are provided in the 'Resolution' part of this article. Resolution You can rectify this issue by trying to open the PowerPoint presentation in an earlier version of PowerPoint. If you are successful in opening the presentation, then insert the slides from the damaged presentation in a new one. Follow the below-mentioned steps: PowerPoint 2002 and 2003 Start the newer version of PowerPoint which gave you the error message Click Insert, and then click Slides from Files In Slide Finder on the Find Presentation tab, click Browse Locate and click the corrupt presentation, click Open, and then click Insert All PowerPoint 2007 On the Home tab, go to Slides group>New Slide, click Reuse Slides In the Reuse Slides pane, Open a PowerPoint file In the Browse box, locate and click corrupt presentation file, and click Open The earlier versions could not detect any type of invalid or damaged data. As a result, the earlier versions can open the presentation, and you may come across a file which exhibits strange behavior. Therefore, in order to recover PowerPoint file efficiently, you must opt for a third-party ppt recovery software. Such tools employ improved scanning algorithms to recover data from corrupt presentation files. Being read-only, these PowerPoint recovery tools do not even modify the original data.