For Windows 7, start by going to the Control Panel > Programsand select Windows Live Essentials to uninstall/change.

But before that, make sure to back up your emails and contacts by clicking on the File menu on the Live Mail app. Go toExport email > Email messages.

Windows 7 Control Panel Programs showing Windows Live Essentials uninstall option
Windows 7 Control Panel Programs showing Windows Live Essentials uninstall option

It will ask you to choose a format, backup location, and the folders you wish to backup.

Select Microsoft Windows Live Mail as the format. Browse and choose a safe location to store your backup, select All Folders or the ones necessary to you, and click Next to Export.

To save your address book, select Contacts on the bottom left pane.

File backup dialog in Windows Live Mail before uninstalling
File backup dialog in Windows Live Mail before uninstalling

Then go to the top menu bar and click Export > Comma Separated Values (.CSV) and save the file to a safe location.

Windows Live Essentials uninstall confirmation screen
Windows Live Essentials uninstall confirmation screen

Now that you have backed up the files, you can select Remove one or more Windows Live programs and click Mail to uninstall.

Programs and Features window showing Windows Live Essentials entry
Programs and Features window showing Windows Live Essentials entry

Download and open the setup file from the Windows Store apps and follow the instructions as before to reinstall the Live Mail app. Import all your backup files, and you're done.

Sometimes, clearing the Microsoft store cache also helps and removes any potential corrupt system files, which you do by typing a command prompt on the Windows search bar and clicking Run as administrative.

Then select Troubleshoot > Additional troubleshooters, then select Windows Store Apps to clean the Microsoft store cache.