What are `Zone.Identifier` files, and how do I prevent them from being created?

Question

I often see files named 'blabla.exe:Zone.Identifier' when monitoring I/O with Process Monitor.
The files are seen on network-drives.

• What are Zone.Identifier files?
• What does the colon mean in the filename?
• Is the colon related the file's extended attributes?
• How do I prevent these files from being created when I copy code files from Windows Explorer to a WSL directory?

Solution

The text after the colon is an identifier for an "Alternate Data Stream". ADS is used to store meta-information about the file. For example, the Zone identifier stores whether the file was downloaded from the internet.

Some specific info: About URL Security Zones, Zone.Identifier Stream Name

Best is to google around for more information. Eg. this, this and this.

Finally, here's Streams, the Sysinternals tool for ADS.

Comments

[hippietrail]

Just the answer I was looking for! But allow me to publicize a good question from another Stack Exchange site: Why shouldn't we use words such as 'here' and 'this' in textlinks?

[Sebastian Wagner]

FYI, the Zone.Identifier Stream Name MSDN Link has changed.

[mguassa]

Dead links have been fixed.

[Timo]

Can I avoid these ADS files as I do not want them? I get them when copying from windows to a wsl folder

[mtness]

To remove problem on Windows side you need to configure it properly. Run gpedit.msc (Win + R) and go to User configuration > Administrative templates >Windows Components > Attachment Manager and set Do not preserve zone information in file attachments. (to run gpedit.msc you’ll need Windows Professional) -- found here: blog.realhe.ro/how-to-get-rid-of-zone-identifier-files