I cannot add or edit the UOM even though I have UOM turned ON and some units assigned to products

Let me help you sort this out, Dianitag39.

Aside from opening the item's setup, we have another way to add or edit the U/M set. Let's try to make some changes from there. It'll help us isolate the issue. Here's how:

1. Click Lists.
2. Go to U/M Set List.

To edit:

1. Select the set, right-click, then choose Edit U/M Set.
2. Make some changes,
3. Click OK.

To add:

1. Click the U/M Set button below.
2. Select New.
3. Select a unit of measure type, then click Next.
4. Select the base unit of measure, then click Next.
5. Click the ADD field for each related unit you want to add, then click Next.
6. Enter the ratio needed, then click OK.
7. Click Next, then select the default unit of measure.
8. Click Next, then enter the set name.
9. Select Finish.

However, if you're still unable to edit or add from there, you may have a corrupted data. We'll have to run the Verify/Rebuild utility to detect the data damage. 

Once done, try to add or edit a unit of measure again.

We're available 24/7 if you need more help from us. Feel free to click the Reply button below. Take care!

Hi Kristine:

Thanks a lot for your response. Unfortunately, as you can see in one of the images of my original post, I am not even getting the U/M Set List under Lists, Quickbooks is literally not giving me any option to add or edit units, only assign the once already created. I'll try to Verify/Rebuild Data and I'll let you know the results. Thank you again.

Just did Rebuild and Verify and the problem is still there. Thanks for the suggestions anyway. 

I appreciate the steps you've tried to resolve the issue, dianitag39.

I'm here to help you ensure you can add/edit the UOM in QuickBooks Desktop.

Let's first update your QuickBooks Desktop to the latest release to make sure you have all the updated components. 

Once done, close the program and download and install QuickBooks Tool Hub. When finished, run the Quick Fix my File option. Here's how:

1. From the tool hub, click the Company File Issues tab.
2. Choose Quick Fix my File.
3. Select OK when it completes and launch your QuickBooks.

If you're getting the same results, proceed to Step 3 in this this article: Fix company file and network issues with QuickBooks File Doctor.

If the issue persists,  I suggest reaching out to our technical support team. This way, they can further investigate the root cause of the issue and provide steps to fix it for you. Here's how:

1. Head to the Contact support page at this link. 
2. Choose QuickBooks Desktop. 
3. Click on Search for something else and enter a brief description of your concern in the search box.
4. Hit Search.
5. Select Start a Message.

I'm always around if you have follow-up questions. 

Thank you! I'll test and confirm.