How do I set Administrator Permissions on folders/files

If the prompt appears while copying between external drives, the usual cause is that the destination folder or files do not grant the current account sufficient NTFS permissions, or the ownership/ACLs on the drive are inconsistent.

Use one of these supported approaches:

1. Grant permissions on the specific folder
   • In File Explorer, right-click the folder that should receive the files, then select Properties.
   • Open the Security tab.
   • Select Edit or Advanced.
   • Add the current user account and grant Full Control.
   • Apply the change.
   This is the recommended approach for a specific data folder. Do not change permissions on Windows system folders such as C:\Windows, System32, or Program Files.
2. If access is denied across the whole external drive, fix ownership first
   • In File Explorer, right-click the external drive, then select Properties > Security > Advanced.
   • Next to Owner, select Change.
   • Set the owner to Administrators.
   • Select Replace owner on subcontainers and objects.
   • Apply the change.
   • Still in Advanced Security Settings, add the current user account and grant Full control.
   • Select Replace all child object permission entries with inheritable permission entries from this object.
   • Apply the change.
   This is useful when many folders and files on the external drive are inaccessible.
3. For an application-specific folder, use a dedicated group
   • Create a local or domain group for authorized users.
   • Grant that group Full Control on the folder by using the folder Security tab, icacls.exe, or PowerShell Set-Acl.

Important:

• Deny permissions override Allow permissions.
• Explicit permissions override inherited permissions.
• Permission changes on a parent folder can propagate to child files and folders.
• Avoid changing permissions on operating system folders.

If the issue happens only when moving or copying files, Windows permission inheritance also matters:

• Copying to another NTFS volume normally makes the file inherit permissions from the destination folder.
• Moving to a different folder on the same volume normally retains the original permissions.

References:

• How permissions are handled when you copy and move files and folders
• When you select Continue for folder access in Windows Explorer, your user account is added to the ACL for the folder
• Windows keeps asking for administrator permissions, when I am the Administrator - Microsoft Q&A
• How to fix permissions - Microsoft Q&A
• How to avoid 'nagging' when copying files - Microsoft Q&A