Default username/password for accessing network shares in Windows 8?

In Windows 7 and 8, there is an option in Control Panel (Credential Manager) that allows you to manage your network credentials. This is a great way to connect to a computer with only having to supply the credentials once. All you need to supply is the computername, username, and password. Save the information

1. Disconnect all network drives
2. Create the credentials
3. Browse to the computername

Hope that helps.

You need to create the account as a local account so that the actual Windows username is the same as on the other devices.
After creating the local account, you can convert/link it to a Microsoft account and everything will still work.