FAQ and Support

We’ve collected some of the most common issues people experienced when trying to use Date Time Duration.

We hope our answers help you out!

How do I add Date Time Duration to my Excel?

To install Date Time Duration, follow the steps on our Instructions page.

How do I use Date Time Duration?

To use Date Time Duration, follow the steps on our Instructions page.

When I try to install, I get this message: “The app you’re trying to install isn’t a Microsoft-verified app”.

Windows is “blocking” the downloaded file. To un-block the file, follow steps 1-2 of the install instructions.

When I try to install, I get this message: “Windows protected you PC. Microsoft Defender SmartScreen prevented an unrecognized app from starting. Running this app might put your PC at risk.”

Windows is “blocking” the downloaded file. To un-block the file, follow steps 1-2 of the install instructions.

When I try to install, I get this message: “This setup requires .NET Framework 4.5.2 to be installed. To install, go to: https://dotnet.microsoft.com/download/dotnet-framework/net452”
  1. Download and install the .NET Framework 4.5.2.
  2. Re-try the install of Date Time Duration as normal.
When I try to install, I get this message: “For Windows XP: Install version 1.0 of ‘Date Time Duration’ from: TumblingWave.com/date-time-duration”
  1. Click the ‘Download version 1.0’ link on the Date Time Duration page.
  2. Follow the instructions to install version 1.0.
I don’t see the arguments for the DATETIMEDURATION formula!

It is normal to not see the formula (or its arguments) in some versions of Excel, because the formula is custom. However, if you type the formula, it will work perfectly fine. Also, if you select the cell and click the “Insert Formula” button , you will see formula details.

I don’t see the DATETIMEDURATION formula!

It is normal to not see the formula (or its arguments) in some versions of Excel, because the formula is custom. However, if you type the formula, it will work perfectly fine. Also, if you select the cell and click the “Insert Formula” button , you will see formula details.

  The DATETIMEDURATION formula gives me #NAME?
  • Date Time Duration is not (fully) installed – follow the steps in our Instructions page to install Date Time Duration.
  • Excel has not loaded the Date Time Duration add-in – to fix, open Excel, select the File menu (or Office button), select Options, select the Add-ins tab. Click Go…, then ensure DateTimeDuration Add-In appears in the list and is checked. If missing, Browse.. for the DateTimeDuration*.xll file under your install folder (typically, your “Program Files” folder).
  • If you still have trouble, ensure your Excel security settings are configured.
The DATETIMEDURATION formula gives me #VALUE!

You are trying to pass a bad argument to the DATETIMEDURATION formula – to fix, follow the instructions on how to use Date Time Duration.

I purchased a license key, but I am not being prompted to enter it.

The trial version prompts occasionally for a license key. So, keep using the trial version until you are prompted to enter your key.

When I try to install, I get this error: “Setup cannot continue because some system files are out of date on your system. Click OK if you would like setup to update these files for you now. You will need to restart Windows before you can run setup again. Click cancel to exit setup without updating system files.”

I get an invalid/expired license message, but I am still in the free trial period (or have purchased Date Time Duration)!
  • Your Windows user security is too restrictive on your PC – Date Time Duration was designed for default Windows security. Contact us for information and for a solution.
  • Your Windows user is not the user who installed the trial version. The trial version should only work for the user who installed the trial version.

Nothing happens when I try to use the DATETIMEDURATION formula!

Your security may be too restrictive – to fix, go to the Instructions page and follow the steps to configure security.

I am having other issues. I can’t get this to work!

Feel free to e-mail Tumbling Wave Support. If you received an Error Code (e.g. Error Code: V9.9-E9999-L99), please include the Error Code in the e-mail.

Send us a new FAQ, and we will add it here!