# Filters and masks

You can hide files in a view by applying a filter or mask:

- A filter omits files from the view entirely. Files that do not pass a filter are excluded from the view. A filter always creates a new view.
- A mask is a filter that is applied to an existing view. A mask hides items that do not pass its filter. The hidden files are not shown but still take up space in the view.

You can apply a mask from the Display tab. You can use a mask amongst others to quickly check if a new filter that you are creating behaves as intended.

From a view with a mask you can use the "Rescan with mask as filter" option from the main menu to create a new window with the mask used as filter. You can also use the Filter command from the "Window" menu to apply a filter to an existing view. It is similar except that it does not rescan your disk and lets you select a different filter if you want.

Use the Filtered scan command from the "File" menu if you want to apply a filter when scanning new data. A filter used this way can greatly speed up scans by skipping folders that you are not interested in.

In the Preferences you can also specify a default filter. This filter is used when scanning unless it is explicitly disabled. It can be disabled by carrying out a filtered scan and disabling the option to apply the default filter.

## Filters and packages

How packages are filtered depends on whether their contents are shown when the filter is applied. If their contents are shown, the package itself is treated as a folder and the filter is applied to all files inside the package. Otherwise, the package is treated as a file by the filter and omitted or included as a whole. When applying an additional filter to an already filtered view, the original filtering logic is used irrespective of the current display settings.

## Find out more

- Editing filters
- Editing filter tests
- How to scan cloud storage - Filters can be used to skip scanning files stored in the cloud.
- How to analyse Time Machine back-ups - Filters can also be used to analyse your Time Machine back-ups.