What “Uninstaller error 2” means when a program updates, and how to get past it
The new version’s installer tried to remove the old version’s files and could not, almost always because the program, or a part of it, was still running. Close it completely, end anything left of it in Task Manager, and run the installer again; a restart clears what is left.
15 October 2026 · 4 min read
What happened
Many Windows programs, especially those built with Electron and installed with an NSIS installer, update by running the new installer, which first runs the old version’s uninstaller to clear its files. If any of those files is still in use, Windows will not let the uninstaller delete it, the uninstaller gives up, and the installer reports it with the code 2. The message often reads “Failed to uninstall old application files. Please try running the installer again.”
The usual reason is timing. An update starts the installer the moment the program begins to quit, and a program can take a few seconds to close its last window, save its settings and end its helper processes. Until then its files are in use.
Getting past it
- Close the program completely, including any icon it keeps by the clock, then run the installer again. This is enough most of the time.
- End what is left in Task Manager (Ctrl+Shift+Esc). Look under Processes for anything with the program’s name, end it, and try again.
- Restart Windows and run the installer before opening the program. A restart releases every file a process held.
- If it still fails, an antivirus program may be scanning the files at that moment. Waiting a minute and trying again usually gets past that.
As a last resort, uninstall the old version from Settings, Apps, and then install the new one. Check first where the program keeps your settings and documents: most keep them in your user folder, which an uninstaller leaves alone, but it is worth knowing before you remove anything.
Is anything lost?
The failed step comes before anything new is installed, so the old version is usually still there and still works. Documents you saved are not touched by an installer. Work you had not saved depends on the program: many keep a recovery copy every few minutes and offer it the next time they start.
Our own product, disclosed
Where our own software comes into this
We make Rutba Office, a free desktop suite for Windows, and some updates to its version 2.0 stopped with exactly this error. Since 2.1 its installer waits for the copy being replaced instead of giving up: it tries again once a second, asks Rutba Office’s windows to close after five seconds, ends what is left of it after ten, and only asks you to retry after fifteen.
Unsaved work is copied for Recover every minute, so a copy closed this way loses under a minute of it at most. Because the new installer does this, the update to 2.1 itself already gets past the error.
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