Setting General Preferences for the MATLAB Application

The MAT-file save format sets the default version compatibility option MATLAB uses when saving MAT-files. Use these options if you use multiple versions of MATLAB or share MAT-files with others who run a different version of MATLAB. The setting applies when you use the save function as well as when you use Save menu items for MAT-files, such as File > Save Workspace As from any desktop tool.

The MAT-file preference also applies to saving FIG-files, which include plots, as well as GUIs you create with GUIDE.

Image of Preferences dialog box showing the MAT-Files panel.

Options are

MATLAB Version 7.3 or later (save -v7.3) — Starting in MATLAB Version 7.3, you can save data that is larger than 2 GB on platforms that allow it, which is the primary purpose of this option. Using this option is equivalent to running save -v7.3. This format of the resulting MAT-file is HDF5-based. You cannot load these MAT-files into any versions prior to MATLAB Version 7.3; in those cases, use one of the other two options.
MATLAB Version 7 or later (save -v7) — Starting in MATLAB Version 7, MATLAB compresses the data when saving a MAT-file, thereby reducing the storage space required. When you load the MAT-file, MATLAB automatically uncompresses the data. In addition, MATLAB uses Unicode^® character encoding for strings when you save a MAT-file, making the data accessible to other users of MATLAB, regardless of the default character encoding scheme used by their systems. MAT-files saved with this option work in all MATLAB 7 versions. Using this option is equivalent to running save -v7.
MATLAB Version 5 or later (save -v6) — Releases of MATLAB prior to Version 7 did not save compressed MAT-files. They also did not use Unicode character encoding, which sometimes prevented the exchange of MAT-files among users, particularly when they used localized systems. Specify this option to save MAT-files for use with versions prior to MATLAB Version 7. Using this option is equivalent to running save -v6.

Like other preferences, the MAT-file save format preference gets its initial value from the preference file for the previous installed version. For example, if the setting in your MATLAB 7.6 preference is -v6, when you upgrade from MATLAB Version 7.6 (R2008a) to MATLAB Version 7.8 (R2009a), the initial value in Version 7.8 is -v6.

If you upgrade from a version prior to MATLAB Version 7.3, or if you do not have a previous MATLAB version installed, the initial value is -v7.

Note For more information about MAT-file save formats, including restrictions, see Version Compatibility Options and Remarks in the save reference page.

Function Alternative

You can override the MAT-file save format preference by using the save function with a specified version compatibility option. For occasional use, this might be more convenient than changing the preference. For example, use save with the-v6 option to ensure compatibility with MATLAB versions prior to Version 7. For more information, see the save reference page.

Confirmation Dialogs Preferences

These preferences instruct MATLAB to display or not display specific confirmation dialog boxes.

Image of Confirmation Dialogs Preferences pane.

When the check box for a confirmation dialog is selected and you perform the action it refers to, the confirmation dialog box appears. If you clear that check box, the dialog box does not appear when you perform the action.

When the confirmation dialog box does appear, it includes a Do not show this prompt again check box. If you select the check box in the dialog box, it automatically clears the check box for the confirmation preference.

For example, select the check box Warn before deleting Command History items. Then select Edit > Clear Command History. MATLAB displays the following confirmation dialog box.

Image of Command History delete confirmation dialog box.

If a confirmation dialog box includes a Do not show this prompt again check box and you click OK, the confirmation dialog box will not appear the next time you perform the action. In addition, the check box in the Confirmations Dialogs preferences pane is cleared.

The following table summarizes the confirmation dialog boxes for MATLAB. There might be additional confirmation dialog boxes listed for other products you have installed.

Confirmation Dialogs Check Box Item	Description of the Confirmation Dialog Box	For More Information
Warn before deleting Command History items	Appears when you delete entries from the Command History window.	Deleting Entries from the Command History Window
Warn before clearing the Command Window	Appears when you clear the Command Window content using menu items. Does not appear when you use the `clc` function.	Clearing the Command Window
Confirm when overwriting variables in MAT-files	Appears when you save variables by dragging them from the Workspace browser onto a MAT-file in the Current Folder browser.	Creating and Updating MAT-Files
Prompt when editing files that do not exist	Appears when you type `edit filename`, if `filename` does not exist in the current folder or on the search path.	Function Alternative for Creating New Files
Prompt to exit debug mode when saving file	Appears when you try to save a modified file while in debug mode.	Ending Debugging
Show linking and brushing message bar	Displays the message bar in a figure window that provides links to help for data brushing and linked plots.	Exploring Data in Graphs
Prompt to save on activate	Appears when you have unsaved changes to a figure and M-file, and then activate the GUI, by clicking the Run button, for example.	GUIDE Preferences in the MATLAB Creating Graphical User Interfaces documentation
Prompt to save on export	Appears when you have unsaved changes to a figure and M-file, and then select File > Export.	GUIDE Preferences in the MATLAB Creating Graphical User Interfaces documentation
Confirm changing default callback implementation	Appears after you have modified a callback signature in GUIDE.	Changing Callbacks Assigned by GUIDE in the MATLAB Creating Graphical User Interfaces documentation
Confirm before exiting MATLAB	Appears when you quit MATLAB.	Quitting MATLAB
Warn about missing search databases	Appears if you have help files in the Help browser for non-MathWorks products and the search database for those files has not been updated for the version of MATLAB you are running.	Contact the provider of the help files to obtain the correct version of the search database. Without the most current version, you can use the help files in the Help browser, but the Help browser search will not include those files in search results.
Confirm when deleting variables	Appears when you delete variables from the workspace using menu items. Does not appear with the `clear` function.	Deleting Workspace Variables

Source Control Preferences

For information, see Source Control Interface.

Specifying Options for MATLAB Using Preferences

Customizing the Desktop Using Preferences

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