Thanks for following up on this thread, 12121212.

I want to make sure you're able to adjust inventory in your QuickBooks Online account.

Since the troubleshooting steps mentioned above didn't do the trick, I recommend reach out to a member of the QBO Support Team. Agents have the necessary tools to take a closer look and determine what's causing the issue to persist. Here's how to get in touch with the team:

1. Click the Help button in the top right corner.
2. Select Contact Us.
3. Enter Support in the field and choose Let's talk.
4. From here you can select to receive a callback at a time that's convenient for you, or begin a live chat session with an agent.

The following linked article provides these steps if you ever need them again in the future: QuickBooks Online Support

Please know I'm only a comment or post away if you have any other questions. Take care!