This is not what we want you to experience, @MHaedike.

Let me share some information so you'd be able to set up the unit of measure feature. Just to clarify, what specific version of QuickBooks are you using? The option to set up the unit of measure is only available in QuickBooks Desktop Premier, Enterprise, and Accountant versions.

If you're using one of the above-mentioned QuickBooks versions, let's first make sure that your QuickBooks program is updated to the latest version. 

Here's how:

1. Go to the Help menu.
2. Select Update QuickBooks.
3. Choose the Update Now tab.
4. In the Options tab, click on the Mark All and choose Save.
5. From the Update Now tab, mark to select the Reset Update checkbox.
6. Click on Get Updates.

Once completed, let's restart your device. This is to make sure that all QuickBooks components are updated. Now, you can open QuickBooks and set up the unit of measure.

Here's how:

1. Click the Edit menu.
2. Choose Preference.
3. Select the Item & Inventory menu.
4. From the Company Preference tab, click the Enable button in the Unit of Measure section.
5. Choose either of the following:
   • Single U/M Per Item
   • Multiple U/M Per Item
6. Click Finish.

If the issue persists, you can run the verify utility and rebuild tool. This way we can isolate this unexpected behavior for data damage.

Leave your comments below if you have other questions about managing inventory in QuickBooks using the unit of measure. I'm always here to help.