Every so often the Xero Menu Bar disappears. I can’t help you to make it magically return, but here are some shortcuts you can use to help you keep working in Xero.

Dashboard https://go.xero.com/Dashboard/
Reports https://reporting.xero.com
Accounts Receivable https://go.xero.com/AccountsReceivable/Search.aspx
Accounts Payable https://go.xero.com/AccountsPayable/Search.aspx
Payroll https://payroll.xero.com
Projects https://go.xero.com/app/projects/
Contacts https://go.xero.com/Contacts/Search/
MyXero https://my.xero.com/