Windows File Extension Reference
Plain-language Windows file extension reference for common document, installer, script, archive, image, media, and system file types.
Files & Storage
Storage problems range from a full drive to a cable that is not seated. These guides emphasize copying important files off a failing disk before running repair tools.
Start here
Choose the closest symptom first. If you are not sure which guide fits, use the PC troubleshooting wizard to narrow the problem before changing settings.
Published topics in this category
- File Recovery (2 guides), Deleted files, Recycle Bin, and what is realistic to recover.
- External Drives (1 guide), USB hard drives and SSDs that do not appear or ask to be formatted.
- Storage Cleanup (2 guides), Finding what is using space and freeing it without deleting the wrong folders.
- File Explorer (2 guides), Explorer freezing, missing folders, and search that does not find files.
- OneDrive (1 guide), Files stuck on "cloud only," sync loops, and OneDrive filling the disk.
- File Permissions (1 guide), Access denied messages and when you should not take ownership of system folders.
Guides
How to Delete a File That Won't Delete in Windows
When Windows says a file is in use, access is denied, or the path is too long, close the locking program and use safe steps, not unlocker downloads from ads.
How to Find Large Files in Windows
Locate what is using disk space in Windows 11 with Storage settings and File Explorer, before you delete folders you do not recognize.
How to Fix a Recycle Bin That Will Not Empty in Windows
When Empty Recycle Bin sits forever, errors out, or files return, close the locking program and reset the Bin, without unofficial "unlocker" downloads.
How to Fix an External Hard Drive Not Showing Up
Find a missing USB hard drive or SSD in Disk Management, assign a letter if needed, and know when "format this disk" would destroy your files.
How to Fix File Explorer When It Keeps Freezing
When File Explorer hangs, turns white, or restarts itself, isolate preview handlers, network folders, and a busy disk before you reset Windows.
How to Fix OneDrive When Files Are Not Syncing on Windows
When OneDrive sits on "processing," never uploads, or files stay cloud-only, pause, sign in, and use Microsoft's reset, without a third-party "sync repair."
Safe Ways to Free Disk Space in Windows 11
Free space on Windows 11 with Temporary files, Recycle Bin, and unused apps, without deleting Windows, WinSxS, or mystery "cleaner" downloads.
What to Do When a Deleted File Is Not in the Recycle Bin
When a file vanishes on delete and never shows in the Recycle Bin, check Shift+Delete, large files, removable drives, and OneDrive. Restore is not an undelete tool.
Related tools
- File Extension Lookup, Look up common Windows file extensions and see what they usually are, what opens them, and when to be careful.