MegaHAL greeting file
File type: Various data file
Files with grt extension are used by MegaHAL software. They are used for some various data used for internal purposes.
Found 2 different file type records with the same grt filename suffix.
File type category:
Various data file
Date updated: September 11, 2017
The grt file extension is associated with MegaHAL, computer program which responds in natural language to what you type, written by Jason Hutchens. It is used for some various data used for internal purposes.
It is not possible to open grt extension files manually by the user.
Files with grt extension are not convertable.
File type category:
Ransomware encrypted file
Date updated: October 25, 2026
Karmen is a ransomware variant based on the HiddenTear project. It encrypts files on an infected computer and adds the .grt file extension when renaming them.
Like other ransomware, Karmen demands payment in Bitcoin in exchange for a decryption key. The .grt extension does not identify the original file format; it indicates that the file was affected by the ransomware.
An encrypted .grt file cannot normally be opened with the program that created the original file. HiddenTear-compatible decryption tools may help recover the data, but their success depends on the specific Karmen variant and available keys.
After decryption, open the recovered file with an application that supports its original format.
There is no useful conversion from the encrypted .grt form to another format. The file must first be decrypted; the recovered original file can then be converted with an application that supports its format.
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