Impress can't read ppt file

I’ve been sent a PowerPoint file (ppt) and when Impress opens it all the text is garbled…mashed together and/or stacked up on top of other text. I was finally able to read the file by downloading MS PowerPoint Viewer. Why can’t Impress read this file? LibreOffice 5.0.3 x64, Windows 10 x64

PowerPoint is a closed non-free file format. Thus, while LibreOffice developers do their best in order to support that format, no one can ensure 100% compatibility. Moreover, since PPT (as well as other file formats of Microsoft Office files prior to 2007) is deprecated, little or no effort will be invested in its support.

Thanks for the reply, gabix. Not sure what version of PowerPoint generated the file. I have experimented and found that FreeOffice, and WPS Office both open and display the file without problems. FYI.