SYSVOL Share is a shared directory on a domain controller on Microsoft Windows Server–based networks that contain the server’s copy of the domain public files, such as group policy objects and scripts for the current domain and the entire enterprise. The contents of this share are replicated to all domain controllers in the Windows Server domain. The default path for the SYSVOL share is \%System_Root%\Sysvol\SYSVOL.
By default, SYSVOL includes 2 folders:
Default location: %SystemRoot%\SYSVOL\SYSVOL\\Policies
All the Group policies which are defined in a particular domain exists under the Policies folder. When you make changes to a particular Group policy object, that change will be committed to the associated GUID name folder under SYSVOL.
Default location: %SystemRoot%\SYSVOL\SYSVOL\\scripts
Note: These default locations can be changed.
Troubleshoot missing SYSVOL and Netlogon shares (Windows Server)
Missing netlogon and sysvol shares typically occur on replica domain controllers in an existing domain, but may also occur on the first domain controller in a new domain.
Domain controllers without SYSVOL shared can’t replicate inbound because of upstream (source) domain controllers being in an error state. Frequently (but not limited to), the upstream servers have stopped replication because of a dirty shutdown (event ID 2213).
Check these two articles from Microsoft to fix missing SYSVOL or Netlogon shares:
How to fix missing SISVOL shares