Why a standard-user scan under-reports C:
Windows protects several folders under C:\Users\<other account>, parts of C:\ProgramData, and some subfolders under C:\Windows so that a normal user account cannot read their contents. When a scanning tool hits one of these folders without administrator rights, it usually shows the folder with a size of 0 bytes or skips it and shows an access-denied marker instead of a number.
The result is a tree that looks finished but is missing exactly the folders most likely to hold forgotten data: another user's downloads, a service's log directory, or an old application's leftover cache. If you're chasing a full system drive and the numbers you see don't add up to the free space Windows reports, this is the first thing to rule out. See our troubleshooting guide for other mismatches between reported and actual size.
Three ways to launch with elevated rights
- Right-click and Run as administrator Find the shortcut or executable in the Start menu or on disk, right-click it, and choose Run as administrator. Confirm the UAC prompt. This is the method most people use for a one-off scan.
- Ctrl+Shift+Enter from Start Open the Start menu, type the program name so it appears in the search results, then press Ctrl+Shift+Enter instead of Enter. Windows launches the highlighted result elevated without needing the right-click menu.
- Set it permanently on the shortcut Right-click the shortcut, choose Properties > Shortcut > Advanced, and check Run as administrator. Every future launch from that shortcut requests elevation automatically, which is convenient if you scan the system drive often but means you'll see a UAC prompt every time, even for quick checks.
What the UAC prompt actually changes
User Account Control decides whether a process runs with a standard token or an elevated administrator token. Elevation does not change who you're logged in as; it changes what the running process is allowed to open. An elevated scan can read folders and file metadata that a standard token cannot, including most system and other-user directories on the local drive.
Elevation is scoped to the process and its children, not to the whole logon session. Close the elevated window and open a new one without the admin shortcut, and you're back to standard-user rights.
The trade-off: mistakes are easier to make
Running elevated removes the safety net that access restrictions provide. A standard account is often blocked from touching system files by design; an elevated session is not. If you delete something from inside C:\Windows or a protected ProgramData subfolder while elevated, Windows will let you, and the consequences range from a broken driver to a system that won't boot.
Treat elevated sessions as read-mostly. Use them to find and measure, then step back to a standard account — or at least slow down and double-check the path — before deleting anything you found while elevated. Our checklist for deleting large files safely is written with exactly this situation in mind.
Where elevation does not help: mapped network drives
A common surprise: you elevate the scanner, and a drive letter you mapped to a network share disappears from the list of available drives, or the scan fails to find it at all. This isn't a bug in the tool — it's a Windows behavior. Drive mappings created in a standard-user session are tied to that user's logon session and are not automatically visible to a process running under an elevated token, even though both are technically the same user account.
If you need to scan a mapped share, either map the drive again from inside the elevated session, or type the UNC path (\\server\share) directly instead of relying on the drive letter. For scanning shares in general, including permission issues that have nothing to do with elevation, see scanning a network drive.
Administrator elevation: common questions
Do I need to run as administrator every time I scan my own user folder?
No. Your own profile folders are readable with a standard account. Elevation only matters when the scan needs to cross into system folders or another account's data.
Why does the drive letter for my NAS disappear after I elevate?
Is it safe to leave a shortcut permanently set to run as administrator?
Will elevation change how big my folders show as being?
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