If you use Outlook on Mac, there is no way to change your theme but you can put it into Dark Mode. Microsoft Outlook has many different features that benefit its users and their workplaces. Outlook 2016 for Mac, Outlook for Mac for Office 365; In this article. Original KB number: 3009176. After you migrate to Microsoft Outlook 2016 for Mac from Outlook for Mac 2011, you notice that the category colors that are assigned to your categories are changed. Outlook for Mac 2011 uses a local list of categories.

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Configure Outlook's Default Setting From the Outlook menu, select Preferences. Click Composing. In the Format and account section of the dialog box, check or uncheck Compose messages in HTML by default. Close the dialog box. Change the Setting for One Message. Change Fonts in Outlook 2019, 2016, 2013, 2010, and Outlook for Microsoft 365 Follow these steps to change the default font in the desktop version of Outlook. If you are working in Outlook 2010, your screens will differ in appearance, but the menu options, locations, and functionality are the same.

Applies to: Exchange Server 2013

A theme defines the background color, fonts, highlight colors, icons, and header that are used by Microsoft Outlook Web App. Each theme is a collection of media files and cascading style sheets (.css) files that are stored on the Microsoft Exchange server in the installation directory in Client AccessOWApremversionresourcesthemes. Each theme is stored in its own subdirectory of themes.

The default theme is found in Client AccessOWApremversionresourcesthemesbase. Each theme folder contains all the files that are needed to define a theme. These files include CSS files, graphics, and an .xml file that defines the name of the theme. Additional themes are created by copying all the files from one theme into a new folder and modifying those files as needed.

By default, multiple themes are installed when you install Exchange Server 2013, as follows:

CSS (.css) files define colors, gradients, and fonts.
Image (.png) files provide the icons and other graphic elements. If you edit any of the icons, don't change their size. If you change the size of any graphic elements, test your changes to verify that the elements still fit together correctly.

These files are stored on the Client Access server in the installation directory in Client AccessOWAprem<version>resourcesthemes. Each theme is stored in a subdirectory of themes. You can create additional themes by copying an existing theme and modifying the copy.

After you create a theme, you may also want to Customize the Outlook Web App sign-In, language selection, and error pages.

Note

The light version of Outlook Web App doesn't support themes.

Warning

If you have multiple servers that support Outlook Web App, you must copy your custom theme to each server. You should also create a backup copy of your custom theme. If you reinstall or upgrade Exchange, all files in the themes folders will be overwritten. You'll have to copy your theme back to the appropriate folder after the reinstallation or upgrade is complete.
Make backup copies of all the files that you'll be changing before you start to create your custom theme.

What do you need to know before you begin?

Estimated time to complete this task: 60 minutes.
You need to be assigned permissions before you can perform this procedure or procedures. To see what permissions you need, see the 'Outlook Web App virtual directories' entry in the Clients and mobile devices permissions topic.
You need local server administrator access to perform these procedures.
You'll need a text editor to change the default colors, and a graphics editor to change the images. If you must match a specific color and you can't find a match for it at Color Table, you can use an image editing tool to sample a color and determine its HTML RGB value.
As a best practice, we recommend that you use the following guidelines any time that you change or create an Outlook Web App theme:
- If you decide to edit an existing theme, make backup copies of the original files before you start editing them.
- Do not delete the folder Client AccessOWApremversionresourcesthemesbase or any of the files in it.
For information about keyboard shortcuts that may apply to the procedures in this topic, see Keyboard shortcuts in the Exchange admin center.

Tip

Having problems? Ask for help in the Exchange forums. Visit the forums at Exchange Server.

Step 1: Create a new Outlook Web App theme

To start, you'll create a folder for a new theme, and then copy the files from an existing theme into the new folder.

Log on to the Exchange server that is hosting the Outlook Web App virtual directory by using an account that has been delegated membership in the local Administrators group.
Open Windows Explorer, and then find the Exchange server installation directory.
In Client AccessOWApremversionresourcesthemes, create a new folder and name it, for example, Fourth Coffee.
Copy all the files from another theme to the new folder.

Step 2: Name your new theme

To set the display name for your new theme, do the following:

Open the copy of themeinfo.xml that's in the custom theme folder you just created.
Find the theme displayname value, and change the value to the name you want to use. For example displayname = 'Fourth Coffee Theme'.
Save and close themeinfo.xml.

Step 3: Change the sort order of your new theme (optional)

If you want, you can change the sort order of the new theme by editing the themeinfo.xml file. The sort order determines the theme position in the Change theme panel in the Settings menu.

To change the sort order of the new theme by using the themeinfo.xml file, do the following:

Open the copy of themeinfo.xml that's in the custom theme folder.
Find the theme sortorder value, and change the value to reflect where you want your new theme to appear in the list. The themes will be ordered by the numeric value in increasing order. By default, the base theme is the first one and its sortorder value is '0'. For example sortorder='<number>'.
Save and close themeinfo.xml.

Step 4: Modify your new theme

Now that you've copied over the files and have named your theme, you can customize it. The following elements can be customized in an Outlook Web App theme:

Image files, which define the header area and icons.
CSS files, which define fonts and colors.

Image files

Theme images are stored in two folders in themes*<theme name>*images. The images0 folder contains images that will be used in left-to-right languages (like English), and languages that are read from right to left will use the images in the imagesrtl folder.

Note

Some of the images in the imagesrtl folder are the same the images as in the images0 folder, but they're mirrored.

To customize the theme, you can use an image editing tool to open and modify the following images:

Headerbgmain.png Charles francatelli.
This is the main header image. We recommend that the image doesn't exceed the header height of 30 pixels. The default theme doesn't use a background image, so this image is transparent. For an example of a theme that has a custom background image, see the image in the Blueprint theme folder.
Headerbgright.png
This is used as a tiling image behind the header. The default theme doesn't use a tiling background image, so this image is transparent. For an example of a theme that has a custom tiling background image, see the image in the Blueprint theme folder.
sprite1.mouse.png
This contains most of the images used in a theme. You can change the color of the images to match your theme

Change Microsoft Outlook Theme Mac