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Q: How do I test autorun.inf files without wasting CD's?

A: It is rather easy to test autorun files from floppy disks or other removable media, but to do so will require a change in the standard registry settings for your computer.

Visit How to Test Autorun.inf Files for the official Microsoft technical information on this topic.

Now, here's the full explanation and step-by-step tutorial for making the changes to your registry to enable floppy autoplay.

1) From the start button menu, select 'run' and type in regedit. This will launch the registry editor.

2) Back up your registry! Not required, but it's always wise to make a backup before changing anything in the registry. From the Registry Editor 'Registry' menu, select 'Export Registry File...'. Give the file a name and save it to the location of your choice. (Should you later need to restore the backup file, use the 'Import Registry File' from the same 'Registry' menu.)

3) Using the same folder tree browsing that you are hopefully familiar with from Windows Explorer, ftp applications, etc., you will need to locate the following entry in your registry:


For your future information, the entries on the left depicted as folders are called registry keys.

4) The area on the right of the Registry Editor will show a list of the various registry values for the 'Explorer' key. The only one you are interested in is 'NoDriveTypeAutoRun'.

The entry for this value varies by operating system and according to which drives currently have autoplay enabled.

For the standard system setup of having autoplay enabled on the CD drive(s), you should see the number 95 in the 'NoDriveTypeAutoRun' value entry. For the standard setup without cd autoplay, this value is normally B5.

On windows 95 and higher, the default with cd autoplay for 'NoDriveTypeAutoRun' is 95 00 00 00.

Don't worry if the value is not 95 or B5. In the case of a non-standard setup, you will wish to make a note of the current value and use the chart given later in this tutorial to create a new value based off that value rather than 95.

5) To change the 'NoDriveTypeAutoRun' setting, you will need to understand a bit about binary and hex values.

To understand this topic clearly, you will need to use the calculator that comes with Windows. From the start button menu, select 'run' and type in calc and hit enter. This will launch the Calculator application.

5a) From the Calculator 'View' menu, select 'Scientific' so that you have the option of displaying a value in both binary (bin) and hexadecimal (hex). Other numerical conversions are available, but these will not be needed.

5b) Set the Calculator to hex and enter 95 (the default setting for 'NoDriveTypeAutoRun' with the cd set to autoplay). Now, switch the Calculator to bin mode. It should display 10010101.

To explore what this number means, you will need to look at it backwards. In other words, the bit order for this number is 7,6,5,4,3,2,1,0.

95 (hexadecimal)
10010101 (binary)
76543210 (bit order)

The chart from Microsoft gives us the following details:
Drive Type = Bit Number
Unspecified Reserved Type = 7

Using the standard boolean (true/false) system, a value of 1 for a bit means the value is true and a value of 0 means it is false.

But, since the registry value is called 'NoDriveTypeAutoRun', you must regard your settings as being:
1 = true = yes, I do not want that drive to autorun.
0 = false = no, I do want that drive to autorun.
Again, this is sort of backwards.

Now, looking at the chart and the binary 10010101 (hex 95) value, you can see that autorun is enabled (0) on bits 6, 5, 3, and 1. This means that drives of type DRIVE_RAMDISK, DRIVE_CDROM, DRIVE_FIXED, and DRIVE_NO_ROOT_DIR will autorun.

Autorun is disabled (1) on bits 7,4,2, and 0. This means that drives of type Unspecified Reserved Type, DRIVE_REMOTE, DRIVE_REMOVABLE, and DRIVE_UNKNOWN will not autorun.

Note: the drive type I am referring to as 'Unspecified Reserved Type' is not actually a type of drive. This is a place holder Microsoft has reserved for future development. It is specified that the 7th bit must always be set to 1.

5c) Floppy drives are removable drives and therefore are of the type DRIVE_REMOVABLE. This drive type corresponds with the 2nd bit in the binary number value and you will want to set it to 0.

6) The easiest and safest way to determine the value for the 'NoDriveTypeAutoRun' entry is to enter 95 (the default setting including cd autoplay) into the Calculator in hex mode. Switch to bin mode and Edit->Copy this value and paste it into a text editor (or write it down). Clear the Calculator (C).

Now, as indicated in above (5c), you need to change the 2nd bit from a 1 to a 0 to enable autoplay on floppy drives (and other removable drives). So, 10010101 becomes 10010001.

With the Calculator in binary mode, enter 10010001. Switch to hex mode and you will discovery that this binary value is equal to 91.

Note: If your system did not start with a value of 95, you will want to go through the same steps to create a custom value based off the number from your system and not 95.

7) Time to enter this new value into the registry. In the Registry Editor, right click on the 'NoDriveTypeAutoRun' entry on the left (as navigated to in step 3). Select 'Modify' from the menu (or click on 'NoDriveTypeAutoRun' and 'Edit' menu->'Modify').

8) In the resulting Edit Binary Value box, enter 91 (the value from step 6) and delete the '95' ('B5' or other value may be in this place as indicated in step 4) leaving the additional 00 or other values in place. Click on the 'OK' button.

9) After reading the rest of this FAQ, close down the Registry Editor and Calculator and restart your computer.

10) Autoplay from floppy disks is not exactly the same as cd autoplay. Most floppy drive controllers do not notify the system when a new floppy has been inserted in the drive and so the auto in autoplay, in this case, is a bit of a false claim.

So, you will be able to test your autorun files and menus, but don't expect it to happen automatically when you insert a floppy into the drive.

To test the autoplay on a floppy, you will need to use Windows Explorer or My Computer. (Note: In tests, I have found My Computer to be the more reliable method.)

With Windows Explorer or My Computer open, insert a floppy disk with an autorun.inf file into the floppy drive. Hit F5 (or 'View' menu->'Refresh') so that Windows will acknowledge the new floppy disk.

Note: You will also need to refresh after any edits and saves of the autorun.inf file even if you have not changed to a new floppy disk.

In Windows Explorer or My Computer, right click on the drive letter for the floppy and select 'Autoplay' from the menu. (Note: My Computer also allows you to simply double click on the drive letter icon to test autoplay.)

To make sure your registry setting change has been done correctly, first test the floppy autoplay method using an autorun.inf file you know works (from a cd or other source) that has been copied to a floppy disk along with any other files required for an accurate launch and display.

From personal experience, I can state that this floppy testing method of autorun.inf files can be a bit buggy. If you are certain an autorun.inf file 'should work' and it doesn't, remove the floppy from the drive, insert a different floppy, refresh, remove that floppy, insert the original floppy with the autorun.inf file and refresh again. This is sometimes necessary after editing an existing autorun.inf file and resaving it to the same floppy. Sometimes just refreshing multiple times clears up the problem as well.

In Conclusion:
I hope you have found this FAQ/Tutorial helpful and that it has given you a full understanding of the process for changing the settings for the autoplay feature of your system.

The binary to hexadecimal information may also assist you in future endeavors in the registry and elsewhere. It was provided to allow you to fully customize the autoplay feature of your system and to enable and disable drive types at will. I thought this to be better than just telling you to set the 'NoDriveTypeAutoRun' to 91 as though it were some magic number of some sort. In other words, I sought to teach and not just tell.

Best of luck with your CD projects;

AshzFall | Autorun.inf Maker