Illegal Windows Names

Written by Eric Wyatt (last updated November 2, 2020)

There is a lot of things we are able to do with our computers, especially with the Windows operating system. As the years go by we gain more and more features, faster and easier ways of doing things. Gone are the days of needing to swap out floppy disks.

Even with the advances in features, some things remain constant. One of those constants for the Windows operating system dates back to MSDOS and has to do with naming files. Due to the continuation of Windows being built on its predecessors, things that were not allowed, or illegal, tend to continue being unallowed. Even if things are not done the same way now they have to continue the tradition due in part to two words—backward compatibility. One of the areas where this is the most prevalent is, as mentioned before, with regards to naming a file or folder on your computer. If you try to use certain names, Windows simply won't allow it. You will get a simple dialog box that says "The specified device name is invalid." (See Figure 1.)

Figure 1. Rename dialog box showing a name can't be used.

Try as hard as you might, Windows will not allow these names for files or folders on your system:

CON COM4 LPT3
PRN COM5 LPT4
AUX COM6 LPT5
NUL COM7 LPT6
COM1 COM8 LPT7
COM2 COM9 LPT8
COM3 LPT1 LPT9
  LPT2

That is it, those are the names that cannot be used for files or folders on any Windows system. As you try to name your files keep these in mind, so even if it makes sense to you to put all of your Corporate Office Newsletters in an abbreviated "CON" folder you can't, and you'll need to come up with a new name. If you want to know about illegal characters check out this tip on character limits.

 This tip (13797) applies to Windows 7, 8, and 10.

Author Bio

Eric Wyatt

Eric Wyatt is a swell guy (or so his friends tell him). He is a formally trained designer and branding expert, bringing a wide range of skills to his Tips.Net articles. ...

MORE FROM ERIC

Historical Weather Information

Historical Weather information can give you insight into what you can expect when it comes to temperature, rainfall, and ...

Discover More

Currency Conversions

The need for currency conversions is an increasing need in a more connected world. The calculator found within Windows 10 ...

Discover More

Quick Event Creation

Windows 10 November 2019 update provides a quick method to add a calendar event. This new method allows you to create an ...

Discover More
More WindowsTips

Working with Compressed Files and Folders via NTFS Compression

Windows 10 provides two ways to work with compressed files and folders. One way is to use NTFS compression, which is ...

Discover More

Creating a Hierarchy Map of Your Hard Drive

Want to see how the directories and subdirectories in your hard drive are organized? It's easy to do using the directions ...

Discover More

Restoring from a Backup

Being able to restore from a backup is just as important as making the backup in the first place. This tip tells you how ...

Discover More
Comments

If you would like to add an image to your comment (not an avatar, but an image to help in making the point of your comment), include the characters [{fig}] (all 7 characters, in the sequence shown) in your comment text. You’ll be prompted to upload your image when you submit the comment. Maximum image size is 6Mpixels. Images larger than 600px wide or 1000px tall will be reduced. Up to three images may be included in a comment. All images are subject to review. Commenting privileges may be curtailed if inappropriate images are posted.

What is 2 + 2?

There are currently no comments for this tip. (Be the first to leave your comment—just use the simple form above!)

Newest Tips
Links and Sharing
OUR COMPANY
OUR PRODUCTS
OUR SITES
 

Copyright © 2024 Sharon Parq Associates, Inc.