Hi @Zoe Hourigan and @JG ,
Thank you for your response, and I apologize for not getting back to you sooner.
Based on the information you provided, I tested this in my own Outlook on the web and was also unable to find the "Save to OneDrive" button. However, I can see a "Save all to OneDrive" option. When I click it, there is a delay and the save operation does not complete successfully.

Given this behavior, and considering that other users have reported experiencing the same issue, I strongly recommend performing the following steps as soon as possible to minimize any impact on your workflow:
These steps must be performed by a Microsoft 365 Admin, If you're not an admin and don't know who the admin is in your organization, you can find guidance here: How can I find my Microsoft 365 admin? - Microsoft Support
1.Contact Microsoft Support Team:


- If your subscription is from a partner or reseller, contact the reseller's support provider to help open a service request on behalf of you instead.
2.Report this issue on Admin Center:
If you're an end-user, you can report this issue via Outlook on the web:
- Open Outlook on the web
- Go to Help > Feedback > Report a problem

- Fill in the form to submit your report.
Your action will assist the Microsoft backend team in investigating and resolving this issue more efficiently. I truly appreciate your effort in helping to address this problem.
If you have any ideas or you find any solution for this problem, please consider replying to this thread. Or if you need any further assistance, please feel free to reply. I'm here and happy to help!