> ## Documentation Index
> Fetch the complete documentation index at: https://docs.ntop.com/llms.txt
> Use this file to discover all available pages before exploring further.

# An unexpected error occurs upon opening files.

## Issue:

When opening a file, the software displays the error "nTop encountered an unexpected error processing the file." Files with a size of 0 kb usually mean the data is corrupt.

![errorunexpected.jpg](https://files.learn.ntop.com/help-articles/interop/errorunexpected.jpg)

## Applies to:

* nTop

## Cause:

This error generally occurs due to the software unexpectedly exiting during the Save process.

## Solution:

Regrettably, a file size of 0 kb usually means the data is corrupt. We cannot restore the file. The best suggestion is to check the Autosave folder for a backup copy.

1. Open nTop
2. Go to **File > Settings**
3. On the left side, click **File Backup.**
4. Check the box to make sure Autosave is active.
5. Next to the Autosave folder, click the icon to browse to the backup directory.

We can potentially restore files with a size larger than 0 kb. Contact support with the problematic file and report any useful details.

More on this topic:

* [nTop Troubleshooting Guide](/help-articles/access-and-installation/setup-and-install-troubleshooting/ntop-troubleshooting-guide)
* [An error message displays when importing a custom block](https://support.ntop.com/hc/en-us/articles/1500002495541)

## Keywords:

*error file processing process encountered unexpected zero bytes corrupt autosave backup recover*