Unable to change outlook data file location

For an IMAP account in classic Outlook, Outlook will always use an .ost file for the mailbox. A .pst file can be added only as an additional data file (for archive/old items), not as the primary store for an IMAP account. To stop Outlook from creating the .ost in OneDrive and instead use a different local path, use one of these supported methods.

1. Create a new Outlook profile and point it to the desired data file location

This method lets Outlook create or use an .ost in a non‑OneDrive folder:

1. If desired, copy any existing .ost from the OneDrive path to the folder where it should reside (for example, D:\OutlookData). This step is optional if a brand‑new .ost is acceptable.
2. Open Control Panel in Windows 11 (press Windows key, type Control Panel).
3. In Control Panel, search for Mail, then open the Mail item that matches the Outlook version.
4. Select Show Profiles.
5. Select Add and give the new profile a name.
6. Let Outlook find the Spectrum IMAP account and select Next.
7. After Outlook finishes the setup, select Change account settings, then Next.
8. In Server Settings, select More Settings.
9. On the Advanced tab, select Outlook Data File Settings.
10. Select Browse and either:
    • Navigate to the copied .ost file in the new folder and select Open, or
    • Navigate to the desired folder, type a new file name, and select Open so Outlook creates a new .ost there.
11. Select Finish to complete account setup.
12. Back in Mail (Control Panel), select Always use this profile, choose the new profile, and select OK.

Outlook will now use the .ost in the chosen location instead of creating it under OneDrive.

To use the old .pst file with this profile, open Outlook and use File → Open & Export → Open Outlook Data File to attach the .pst as an additional data file. Items can then be dragged/copied from the .pst into the IMAP mailbox if needed.

2. Force all new .ost files to a specific path (for new profiles only)

If the goal is to redirect all future .ost files away from OneDrive, configure the ForceOSTPath registry value before creating a new profile:

1. Select Start → Run, type regedit, and select OK.
2. Go to: HKEY_CURRENT_USER\Software\Microsoft\Office\xx.0\Outlook
   (xx.0 is the Office version, for example 16.0 for Microsoft 365/Office 2016+.)
3. Right‑click Outlook → New → Expandable String Value.
4. Name it ForceOSTPath.
5. Right‑click ForceOSTPath → Modify.
6. In Value data, enter the full folder path where .ost files should be stored (for example, D:\MyOST) and select OK.
7. Close Registry Editor.
8. Create a new Outlook profile and add the Spectrum IMAP account; the .ost will now be created in the folder specified by ForceOSTPath.

Note: ForceOSTPath only affects new profiles and involves registry editing, so a registry backup is recommended before changes.

References:

• You can't change the location of the offline Outlook Data File (.ost) in Microsoft Outlook
• Find and transfer Outlook data files from one computer to another