Drive Notify is a program designed to allow you to be asked to connect your backup drive if it's not connected when a True Image backup task is run. Since the Acronis True Image family of programs pre/post-commands of a task don't support interactive commands (commands that require user input) or running programs that require a GUI, this isn't something that can be done directly with True Image.
Drive Notify gets around this problem. In addition to displaying a message and pausing the backup until the desired drive is connected, it can also be configured to automatically proceed with the backup if the drive is already connected or when it is connected without any further user intervention.
Drive Notify currently doesn't have an installer program and must be installed manually. Download the ZIP file and extract the contents into the folder in which you want Drive Notify installed. The recommended folder is DrvNotify in the root folder of the Windows drive. For example: C:\DrvNotify

Click here for the download link and information on the limitations of the free version.
Click here for information regarding the purchased version.
I highly recommend this great little program which is very easy to setup and use. I personally have used it for several months to always notify me as to when my backup storage drive needs to be attached. (Safety dictates it should not be attached when not in use.) I liked the program so well, I purchased the paid version for the convenience of using the AutoContinue feature. -- GroverH
Drive Notify needs to be running before the True Image backup task starts in order to function properly. This can be accomplished by adding a shortcut to DrvNotify.exe to the Programs >> Startup menu (recommended), starting the program manually or setting up the Windows Task Scheduler to start the program before the True Image task starts. Note that no program options are used when starting Drive Notify so it runs in the background.
Once Drive Notify is running, you can run it again using options to have it display a message or wait for a drive to be connected. These are the options used in the pre-command of the True Image backup task. You can also setup shortcuts with these options to use for testing.
The options available are:

Both the /wait and /wait:exit options can take a second option to specify the desired drive. If no drive value is specified, Drive Notify will run in manual mode and use the default settings.
Here is an example of the message displayed using the /wait option:

Here is an example of the message displayed using the /wait wd320 option:

All messages and drive settings are contained in the DrvNotify.ini file and can be edited as desired.
To add a custom drive for use with Drive Notify, you must edit the DrvNotify.ini file and add a new section for it. The section heading is the name you're giving the drive. For example: You have a Western Digital 320GB USB drive and you want to use it with Drive Notify. You decide to name it wd320 and it is assigned the J: drive letter when connected. You want Drive Notify to automatically proceed with the backup. In this example, you would add the following section to the DrvNotify.ini file:


The message you want displayed needs to be typed in all on one line (it will wrap in the displayed message box). If AutoContinue is not specified or it is set to 0 (zero), the AutoContinue function will be disabled and you will need to click the Proceed button after connecting the drive.
If the AutoContinue option is used, you will need to create a file named drvnotify.txt in the root folder of the drive. A sample file is included for wd320. The file is just a standard text file and can be created using the Windows Notepad program. It just needs to contain the drive value (wd320, in this example).
When the AutoContinue option is used, it functions in the following way: When Drive Notify is called, it looks for the drive specified (in this example, J:). If it doesn't find the drive, it waits. If it finds the drive, it looks for the drvnotify.txt file in the root folder. If it finds the file, it reads the first line and checks if it's the desired drive (in this example, wd320). If it isn't a match, the program continues to wait. If it is a match, the program will continue automatically. Using this method allows multiple drives to use the same drive letter and still be detected as separate drives for backup purposes.
Here is more detailed information on the Drive Notify options.

This option tells Drive Notify to display the message associated with the drive specified or the default message if no drive is specified. If the AutoContinue option is not used, you must click the Proceed button to allow the backup to continue.

This option functions exactly the same way as the /wait option except that it exits the Drive Notify program after it's done. This option is provided for those users that don't want extra programs running in the background. By using the Windows Task Scheduler to start Drive Notify before the True Image task starts and then using this option, the Drive Notify program will only be running when needed.

This option tells Drive Notify to exit. It can be run as a post-command in a True Image task or from a shortcut to exit the program. Note that you can also exit the program by running it again with no options and selecting to close it when asked.
Here are several sample scenarios for using Drive Notify.
Scenario #1: Drive Notify is setup to run when the computer starts. Several backup tasks are created and Drive Notify is called using the /wait [drive] option.
Scenario #2: The user only runs one backup task per day and doesn't want
Drive Notify to be left running in the background. Drive Notify is setup to run when the computer starts.
The task is setup to call Drive Notify using the /wait:exit [drive] option. This
exits Drive Notify when the backup starts. This method assumes that the computer is started every day
before the task runs. Otherwise, the Drive Notify program will not be restarted.
Scenario #3: The user doesn't want Drive Notify to be running in the background, but has one or more backups scheduled. Drive Notify is setup to be started by the Windows Task Scheduler before the True Image task runs and the /wait:exit [drive] option is used. For example: A backup task is scheduled to start at 9:00am. Windows Task Scheduler is setup to start Drive Notify at 8:55am. The True Image task runs at 9:00am, calls Drive Notify which then exits when finished.
You can test Drive Notify by testing the command when setting up a True Image task or by setting up shortcuts that contain the desired options. Below are several examples of shortcuts:
Using /wait

Using /wait wd320

If you have problems and need to start over fresh, make sure to check the Task Manager and verify that DrvNotify.exe is not running. If it is, terminate all copies of the DrvNotify.exe program before you start testing again. Also, delete the DrvWait.ini file (if it exists) in the Drive Notify installation folder. This will make sure that the testing is beginning from a clean starting point.
Here is a screenshot of Drive Notify setup in the pre-command section of a True Image
backup task.
In this example, it's using the /wait wd320 option:

Please note that the Do not perform operations until the command's execution is complete option needs to be checked (the default). Otherwise, True Image won't wait for the drive to be connected and the task will fail.
If you test the command using the Test command button, Drive Notify should work properly if properly configured. True Image will pop-up a Command Prompt window during the test (just ignore it).
There are currently some undocumented options available in the purchased version. I hope to have them listed soon.
A FAQ page is planned, the contents of which will depend upon feedback from users of the program.
If you have any questions or problems with the program, please contact: support@themudcrab.com