Fix your audio drivers. Hardware problems can be caused by outdated or malfunctioning drivers. Make sure your audio driver is up to date and update it if needed. If that doesn't work, try uninstalling the audio driver (it will reinstall automatically).

If you can't sign in to your Outlook.com, Hotmail, Live, or MSN email account, or you're not sure how to sign in or sign out, here are some solutions.

Post questions, follow discussions and share your knowledge in the Outlook.com Community. You can give feedback by selecting Help from the top menu, then Feedback. If you need help with Outlook.com, you can read our self-help content, or get support via email.

If your system is asking you for your BitLocker recovery key, the following information may help you locate your recovery key and understand why you're being asked to provide it. Important: Microsoft support is unable to provide, or recreate, a lost BitLocker recovery key.

Get help and training for Office products, such as Word, Excel, PowerPoint, and Outlook. Learn tips and tricks, troubleshoot issues, and access online resources.

Change from a 32-bit version to a 64-bit version or vice versa. Activate Windows. Fix Bluetooth problems in Windows. Learn how to install, reinstall, or activate Microsoft 365 or Office 2019 on a PC or Mac.

The VLOOKUP and HLOOKUP functions, together with INDEX and MATCH,  are some of the most useful functions in Excel. Note: The Lookup Wizard feature is no longer available in Excel. Here's an example of how to use VLOOKUP. =VLOOKUP (B2,C2:E7,3,TRUE) In this example, B2 is the first argument —an element of data that the function needs to work.

Add a shared mailbox to Outlook mobile. Open a shared Mail, Calendar or People folder in Outlook for Mac. Learn how to open a shared mailbox in Outlook. Shared mailboxes let a group of users view and send email, and share a calender, and open a contact list from a common mailbox.

Change your password with your email provider. See the following sections for instructions on changing your email account password for several major email providers. If your email account provider isn't listed, contact your admin or the email provider's help desk.

If your purchase of Office or Microsoft 365 came with a product key, you enter your product key on one of the websites listed below for your product. After you enter your key, you can download and install Office, or you can renew your Microsoft 365 subscription. Tip: Get tech expertise with Business Assist.