What version of Premiere Elements and on what computer operating system is it running?
For now I will assume Premiere Elements 13/13.1 on Windows 7, 8, or 8.1 64 bit and NTSC setup.
Let us start with your project preset. Are you setting it manually or letting the project do it automatically?
Whatever the case, is the project preset
AVCHD LITE 720p60
If that is set, then when you are in the workspace Edit Menu/Project Settings/General, you should see the
If the project is not doing the project setting correctly based on its analysis of the properties of the first video dragged
to the Timeline, then you set the project preset manually.
File Menu/New/Project and Change Settings.
In Change Settings, change the project preset to the AVCHD LITE 720p60 one mentioned. OK out of there.
In the New Project dialog that opens, rename the project, and make sure to have a check mark next to "Force
Selected Project Settings on This Project". OK out of there.
The in the Expert workspace, import your GoPro using Premiere Elements' Add Media/Files and Folders/Project
Assets from where you drag the file to the Timeline.
At that point, the video should present on the Timeline with no colored line over it. What does the playback
look like and sound like in Edit area monitor?
Right click the Edit area monitor, select Playback Quality and decide between Automatic and Highest.
Look into Edit Menu/Preferences/General and "Timeline render quality (valid for HD projects" setting.
If is comes to it, we could discuss the use of the 3rd party Neat Video filter. But let us weight all the factors first.
Is your video card/graphics card up to date according to the web site of the manufacturer of the card?
Is this problem restricted to just the GoPro footage?
Please review and consider.