Altium has done recently quite a lot of new updates. In the case you are trying to open the original iMX6 Rex files with the new Altium 2014 you will get some DRC violations. Have a look at Randy’s Clemmons post where you can find the steps about how to fix it: Porting iMX6 Rex to AD14.

Basically, you need to repour all the polygons and setup new differential pair rules (this was the biggest change between AD13 and AD14). For the Base board we also recommend you to disable the new Altium rule which is checking all the silkscreen outside of the board area. The new iMX6 Rex AD14 files can be downloaded from here.

I still highly recommend you to read the Randy’s post, as this will help you exactly understand the AD14 changes and it may help you when you will be porting different projects.

Thank you Randy! A fantastic post!