Hello, Welcome to MalwareTips.
I'm nasdaq and will be helping you.
If you can please print this topic it will make it easier for you to follow the instructions and complete all of the necessary steps in the order listed.
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The extension .coot is associated with a ransomware infection called STOP.
To confirm please send a sample of a file to this forum.
Upload a ransom note and/or sample encrypted file to identify the ransomware that has encrypted your data.
id-ransomware.malwarehunterteam.com
They will inform you if the files can be restored or not.
My personal opinion is that you will need to restore your file from a personal backup if available.