| Original | After rename | |---------------|---------------| | readme | readme.txt | | data_2025 | data_2025.txt | | file.tar | not selected (has extension) |
PowerRename provides an efficient, regex-driven method to add extensions to extension-less files without affecting correctly named files. By using the pattern ^[^.]+$ to select target files and ^(.+)$ → $1.txt to rename, users can restore file type associations in bulk. This approach reduces manual errors and is reversible, making it ideal for data cleanup tasks.
Note: PowerRrename's "Extension only" option won't work because there's no extension to replace. So we rename the entire name. powerrename add extension to files without extension
: Ensure the "Apply to" dropdown is set to "Filename only" or "Filename + Extension" . If it is set to "Extension only," PowerRename may ignore files that don't already have one.
PowerRename remains the safest for GUI users, offering undo via in File Explorer. If it is set to "Extension only," PowerRename
: If you make a mistake, you can usually undo the last operation by pressing Ctrl + Z while the PowerRename window is still active.
AI Research Desk Date: April 14, 2026 Software Version: Microsoft PowerToys (PowerRename utility) AI Research Desk Date: April 14
Right-click a folder containing target files → Show more options → PowerRename .
: In the Apply to dropdown, select Filename only .