When you download files from the Internet, Windows 11 shows you a security warning every time you try to open it by default. Some file types are blocked from opening.
TheÂ Attachment ManagerÂ is included in Windows to help protect your PC from unsafe attachments that you might receive with an e-mail message and from unsafe files that you might save from the Internet. If the Attachment Manager identifies an attachment that might be unsafe, the Attachment Manager prevents (blocks) you from opening the file, or it warns you before you open the file.
It uses theÂ IAttachmentExecuteÂ application programming interface (API) to find the file type, to find the file association. When one of these applications saves a downloaded file on a disk formatted with NTFS, then it updates the metadata for the file with the zone it was downloaded from. The metadata is saved as anÂ Alternate Data Stream (ADS). If you wish to unblock a downloaded file, you can do so by right-clicking it, selecting Properties and clicking onÂ Unblock.
The following determine whether you are prevented from opening the file or whether you are warned before you open the file:
The Attachment Manager classifies files that you receive or that you download based on the file type and the file name extension. Attachment Manager classifies files types as high risk, medium risk, and low risk.
If you like, you can addÂ UnblockÂ to the context menu of files and folders to make unblocking files easier to do as needed.
When you click onÂ UnblockÂ in the context menu of a blocked file, you will be prompted by either aÂ Open File – Security WarningÂ orÂ Windows Defender SmartScreenÂ dialog to approve unblocking the file without opening or running the file.
When you click onÂ UnblockÂ in the context menu of a folder, you can select toÂ Unblock files in folderÂ orÂ Unblock files in folder and subfolders. You will not get prompted by aÂ Open File – Security WarningÂ orÂ Windows Defender SmartScreenÂ dialog to approve.
This tutorial will show you how to add or remove anÂ UnblockÂ file context menu to files and folders for all users in Windows 10 and Windows 11.