Fixing ERROR_FILE_READ_ONLY (0x1779) in Windows 10/11

When This Error Hits

You've been working on a document or config file all morning. You hit save — and Windows throws up ERROR_FILE_READ_ONLY (0x1779). The file stays open, but that last hour of edits is gone. This happens most often with files you've copied from a CD/DVD, pulled off USB drive that was on a locked-down system, or extracted from a zip archive that preserved the source's read-only flag. Also common with config files in C:\Program Files or C:\Windows\System32 that the OS protects by default.

Root Cause (Short Version)

The file has its read-only attribute set at the filesystem level, plain and simple. Windows checks this flag before letting any process write to the file. If it's set, the write operation gets blocked and you see error code 0x1779. Sometimes it's the file itself, sometimes the folder it's in — or NTFS permissions overriding things. But the culprit here is almost always the read-only attribute.

Fix It in 3 Steps

Don't bother with driver updates or reinstalling apps. That's not the issue. Here's what works.

Step 1: Check the File's Read-Only Attribute

1. Right-click the file in File Explorer and select Properties.
2. On the General tab, look at the Attributes section at the bottom.
3. If Read-only is checked, uncheck it. Click Apply, then OK.

That's the fix 90% of the time. If it's grayed out or won't stay unchecked, move to Step 2.

Step 2: Use Command Line to Force Clear It

Sometimes File Explorer lies to you — the attribute is stuck. Use attrib to blast it off.

attrib -r "C:\path\to\your\file.ext"

Replace the path with the actual file path. If the filename has spaces, keep the quotes. This removes the read-only attribute from that file only. To remove from a folder and everything inside it:

attrib -r "C:\folder\*.*" /s

The /s flag recurses into subfolders. Yes, that includes hidden and system files — it's aggressive, but it works.

Step 3: Check NTFS Permissions (If Still Failing)

If the attribute is clear but the error persists, NTFS permissions are blocking you. Here's how to check:

1. Right-click the file or folder → Properties → Security tab.
2. Click Advanced.
3. Look for the Permissions tab. Make sure your user account has Modify or Full control.
4. If not, click Add → Select a principal → type your username → check Modify → OK.

You can also use icacls to grant full control from command line:

icacls "C:\path\to\file.ext" /grant "%username%":F

Still Failing? Check These

You've done all the above and the error won't budge. Here's what to check next:

• Is the file open in another program? Sometimes another process holds a lock. Close all programs, or use handle.exe from Sysinternals to see who has it open.
• Is the file on a network share or external drive? The share might have read-only permissions set server-side. Contact your IT admin.
• Is the file compressed or encrypted? NTFS compression and EFS encryption can cause weird write blockers. Try moving the file to a non-compressed folder first.
• Third-party antivirus? Some AV suites (looking at you, McAfee) add their own read-only protection. Temporarily disable it to test.

If none of that helps, the file might be on a failing drive. Run chkdsk /f on the drive to check for filesystem corruption. But honestly — that's rare. 9 times out of 10, it's just the read-only attribute. Uncheck it and move on.