Syncing issues with my gmail account in classic outlook?

Dear Andy Vierra, 

Thank you for reaching out here in the Microsoft Q&A forum. 

I fully stand on your shoes when knowing that you are facing a critical syncing incident with your Gmail account in Classic Outlook, especially after switching back from the new version, and I understand your confusion.

To better understand and investigate this incident, I may need some more detailed information from your side: 

• What is the exact version and build of your Classic Outlook application? (You can find this by going to File > Office Account > About Outlook). 
• When setting up your Gmail account, did you configure it as IMAP or POP? 
• Did you enable IMAP access within your Gmail settings in a web browser before adding the account to Outlook? 

Since the incident started after switching versions, the Outlook mail profile may be experiencing an incident. Here are a couple of methods we can try: 

Method 1: Create a New Outlook Profile  

This creates a fresh environment for your accounts and is often the most effective way to resolve profile corruption. 

1. Close Outlook. 
2. Press the Windows Key + R, type control panel, and press Enter. 
3. View by Large icons and open Mail (Microsoft Outlook). 
4. Click Show Profiles > Add. 
5. Give the new profile a distinct name (e.g., "Outlook Test") and click OK. 
6. Follow the prompts to add your Gmail account to this new profile. 
7. Set this new profile as the default or choose the "Prompt for a profile to be used" option. 
8. Restart Outlook and select the new profile. 

Method 2: Remove and Re-add the Gmail Account 

If the issue is specifically with the account connection, this forces a fresh sync. 

Disclaimer: Before you remove any account, please ensure you have backed up any local data (like POP files or local archives) to prevent potential data loss. 

1. In Outlook, go to File > Account Settings > Account Settings. 
2. Select your Gmail account and click Remove. 
3. Restart Outlook. 
4. Go to File > Add Account to re-add your Gmail account. 
5. Follow the on-screen authentication prompts. You can also use this guide for reference: Add a Gmail account to Outlook for Windows - Microsoft Support 

I look forward to your next update for further analysis, especially the Outlook version and the results of trying the new profile. Please feel free to let me know how it goes.

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