Persistent “Unknown Error” Loading Motion Graphics Template

what helped me at the end: I opened a new project and imported some simple iPhone footage (1920/1080) with 30p. I created a sequence and imported the Motion Graphic template that was causing a problem in my current project (sequence 25frames, 4k material). Here it worked without the error message.  Now i simply copied the imported Motion Graphic, opened my 4k project and simply pasted the Motion graphic on my sequence. It worked ! No error warning. This was my successfull and simple work around. Maybe it helps others to.

Para mim foi apenas o diretório do arquivo aonde eu salvei o projeto que estava muito longo e com pastar nomeadas com virgulas. Reduzi o nome da pasta aonde estava alojado o projeto do adobe premiere, retirei as virgulas deste mesmo nome de pasta, e tudo voltou ao normal.

None of this works for me, the error did not occur before with all my assets, but when I added a new asset to motionbro, suddenly, all my assets, even the ones that were not from motionbro, stopped working, what just happened ?

If you are saving to an cloud/external hard drive...I might have a solution for you below ( @BIGBOY PRODUCTIONS )

Here's the thing...it seems (as true with most glitches) there are SEVERAL triggers that could cause this problem...not just one. So, the solution from someone that says - "this one simple thing in 30 seconds fixed it" - might not be the magic solution for your problem.

First, try everything that @Peru Bob said.... @Peru Bob has given the best exhaustive list that I found anywhere in the support community. I am only adding another trigger to this list...none of these is the end all/fix all.

My glitch was caused by working in a synchronized folder to the cloud.

I normally do all my work in a synchronized folder to a cloud application (e.g. Google Drive, Box, OneDrive, Adobe Creative Cloud, etc)

After updating, Adobe Premiere seemed to not like the cloud app I was using. I tried all other methods of fixing this issue...none worked...UNTIL...

I accidentally created a Adobe Premiere project that saved to a location on my hard drive...and the Motion Graphics Template Import Error was gone! Here is what I did...

• Create an Adobe Premiere project on your hard drive (not a synchronized folder to any cloud app)
• Create a sequence. Open Essentials Graphics (Window > Essential Graphics), Browse, and drag the MOGRT files from your library onto the sequence. In your Adobe Premiere Project bin, this will create a folder called Motion Graphics Template
• Create an Adobe Premiere project on your synchronized folder.
• Copy and Paste (right click Copy/Paste or Ctrl-C/Ctrl-V works) the Motion Graphics Template folder in the Adobe Premiere Project bin from the hard drive Premiere Project bin to the synchronized folder Premiere Project bin.

I hope this additional solution works from some of you.

Where is the mogrt from? Adobe Stock or a third party?

Can you open it in After Effects?

Delete the Media Cache and Media Cache files:
https://community.adobe.com/t5/premiere-pro/faq-how-to-clear-your-media-cache-in-30-seconds-in-premiere-pro-2020/m-p/11017257/thread-id/260446?page=1

If that doesn't work, try resetting the preferences:
https://community.adobe.com/t5/premiere-pro/faq-how-to-reset-trash-preferences-in-premiere-pro/td-p/8236158?page=1

If that doesn't work, try resetting the Workspaces:
Reset a workspace
Reset the current workspace to return to its original, saved layout of panels.
1. Do one of the following:
• Click the Workspace menu icon and select Reset to Saved Layout.
• Choose Window > Workspace > Reset to Saved Layout.
from here:
https://helpx.adobe.com/premiere-pro/using/workspaces.html

If that doesn't work, try Preferences > Audio Hardware and set Input to None.

If that doesn’t work, try updating or rolling back your graphics driver directly from the video card manufacturer’s site. If NVIDIA, do a clean installation of the latest Studio Driver (NOT the Game Driver)

If that doesn't work, try creating a new project and import the old one into it.