Hello, I hope someone can assist. I have installed 17 on 2 laptops and 17.1 on another all with windows 8 upgraded to 8.1 Now I have a new PC with 8.1 and cannot get 17.1 to install. I go thru all the steps but when I get past "something else" and choose the "free space" that I partitioned in windows and hit install the window pops up with "no root file system is defined" "Please correct from partitioning menu.. I have never had this happen, did I not do something? There is 1 300mb(fat32, efi) partition, ntfa, free space(which is where I am trying to install Linux), 1 small and 1 large "free space". Then the define for boot loader installation, which I do not remember needing to do before. Can someone please help. The PC is an Acer Aspire, amd10, 3.7ghz, quad core, radeon hd 8670 graphics , 1 terabyte hdd, 4gb ram, windows 8.1

Sorry, FYI.....I disabled fast boot and secure boot and put 8.1 boot manager on the bottom in list of priority. I have never had the window pop up with "no root file system defined" before.

The no root filesystem defined means you did not select a mount point which you can do after highlighting free space in the main window, click the + tab below the window on the left and you should get a new screen to select the space, a filesystem type and size. If you have windows 8 installed in UEFI, you need to do the same with Mint. I don't use UEFI so can't give any more details on that.