# Estimation has been interrupted

**URL:** <https://kopia.discourse.group/t/estimation-has-been-interrupted/9046>\
**Category:** Support\
**Created:** [November 2, 2026, 9:34am UTC](https://kopia.discourse.group/t/estimation-has-been-interrupted/9046 "2026-11-02T09:34:23Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Audiogio](https://avatars.discourse-cdn.com/v4/letter/a/e5b9ba/32.png) [@Audiogio](https://kopia.discourse.group/u/Audiogio)\
**Post date:** [November 2, 2026, 9:34am UTC](https://kopia.discourse.group/t/estimation-has-been-interrupted/9046/1 "2026-11-02T09:34:23Z")

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I have setup a daily backup starting at 3:30 of about 1.7 TB source producing about 1.9TB backup since a couple of years on an external 4TB USB disk.   
Apparently it works very well, the daily check has never found any missing file, and when I had to recover any lost file I have always been able to find it. Howerver very often in the log file I find this situation:

…  
| 03:49:41.558 snapshotted directory `{"path":"MyAlbum","dur":"2m27.1946951s","size":641679212968,"files":113654,"dirs":2274,"errors":0}` |  
| 03:49:41.559 snapshotted directory `{"path":".","dur":"19m35.5611618s","size":1667152840498,"files":839547,"dirs":48958,"errors":0}` |  
| 03:49:41.559 Estimation has been interrupted |  
| 03:49:41.562 keeping 2025-02-28 23:30:00.0260881 +0100 CET retention: [monthly-20] pins: [] |  
…  
03:49:41.562 created snapshot 4754998f196770d25770e9b1035240df

What does it mean “Estimation has been interrupted”? Is still there some kind of timeout that stops the process after a few hours? I can’t remember of setting it up, but after a couple of years I am not sure.

Thank you in advance

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<div class="post-metadata">

**Author:** ![dimejo](https://yyz2.discourse-cdn.com/free1/user_avatar/kopia.discourse.group/dimejo/32/287_2.png) [@dimejo](https://kopia.discourse.group/u/dimejo)\
**Post date:** [November 4, 2026, 9:12am UTC](https://kopia.discourse.group/t/estimation-has-been-interrupted/9046/2 "2026-11-04T09:12:23Z")

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Looks like the error comes from this PR:

> <https://github.com/kopia/kopia/pull/4218>
>
> Currently, to estimate amount of data to be processed, we need to iterate over a…ll the data. This slows down hashing and also can take too much time when we have big amount of files.
> 
> This PR brings an improvement, now it's possible to use rough estimation, which is usable when we are snapshotting whole volume. In such case we can get filesystem stats (as \`df\` does) and use amount of data / number of files for estimation.
> 
> This new mechanism is available under the flag \`./kopia snapshot create /some/path --progress-estimation-type=rough\`
> 
> When using this flag, user needs to understand, that in such case any ignore rules are not taken into account and estimation could be a bit inaccurate.
> 
> In some cases it may worth to fallback to classic estimation to have more precise estimation of data to be uploaded.
> 
> This "adaptive" mechanism will also be available under the flag \`kopia snapshot create /some-path --progress-estimation-type=adaptive --adaptive-estimation-threshold=10000\`

Kopia estimates the backup size before snapshotting to show accurate progress information. For large snapshots this can take a lot of time, so Kopia stops iterating over all files and uses a different method for rough estimation.

Conclusion: Nothing to worry about.