LastPass can backup WLAN passwords in MacOS and Windows, but can only restore them in Windows.

• To backup, on your browser click LastPass Icon > Tools > Import From > WiFi Passwords (or Other > WiFi Passwords)
• To restore, on your browser click LastPass Icon > Tools > Export To > WiFi Passwords (or Other > WiFi Passwords)

For more details, read their instructions.

NOTE: LastPass only backs up WLAN passwords from adapters that are still installed, i.e., only those WLANs appearing in "Control Panel\Network and Internet\Manage Wireless Networks". Therefore, BACK UP THE PASSWORDS FIRST before uninstalling the WLAN adapter device driver.

Windows 7 itself lets you back up and restore passwords via a USB flash drive, but only one by one.

WirelessKeyView can retrieve the passwords and save them as a text file or in HTML, but cannot restore them. NOTE: WirelessKeyView retrieves passwords even in those adapters you've already removed.