Outlook Not Responding or Stuck on Loading Profile: 10 Fixes

Written by the Softkeyworld technical team · Updated October 2026

"Outlook (Not Responding)" in the title bar, a splash screen frozen on Loading Profile or Processing, or a window that turns white whenever you click a folder. These are among the most common Office complaints we deal with, and the cause is almost never Outlook "being broken". It's usually one of a short list: an add-in, a damaged data file, a corrupt profile, an oversized mailbox, or a sign-in prompt stuck behind the main window.

The fixes below are in the order we'd try them on a customer's PC: quickest and least disruptive first. They apply to classic Outlook in Microsoft 365 and Outlook 2016, 2019, 2021 and 2024 on Windows 10 and 11. There's a separate section for the new Outlook for Windows.

Symptom, likely cause and first fix

What you see	Most likely cause	Start with
Stuck on "Loading Profile" splash screen	Add-in, corrupt profile, compatibility mode, hidden credential prompt	Fixes 1, 2, 3, 8
Stuck on "Processing"	Startup add-in or damaged settings	Fix 2 (safe mode), then Fix 4
Opens, then "Not Responding" when switching folders	Large or damaged .pst/.ost, oversized folders	Fixes 6 and 9
Freezes when opening or sending an email	Antivirus or other email add-in, rendering issue	Fixes 3 and 10
Hangs after an Office or Windows update	Partially applied update, damaged install	Fixes 5 and 7

Fix 1: Check for a hidden dialog and let current work finish

Before changing anything, rule out the two "non-faults". Outlook often looks frozen because a dialog box is waiting for you behind the main window. That might be a password prompt, a certificate warning or a "do you want to save?" question. Press Alt + Tab and cycle through the windows. Also check the status bar at the bottom of the Outlook window. If it says it's updating a folder, applying rules or archiving, give it a few minutes, especially after moving thousands of messages at once.

If Outlook is truly stuck, open Task Manager (Ctrl + Shift + Esc), select Microsoft Outlook, choose End task, and make sure no OUTLOOK.EXE process remains on the Details tab before you try again.

Fix 2: Start Outlook in safe mode

Safe mode starts Outlook without add-ins, customised toolbars or the reading pane extensions. It's the single most useful diagnostic step.

1. Close Outlook completely.
2. Press Windows + R, type outlook.exe /safe and press Enter. Alternatively, hold Ctrl while clicking the Outlook icon and confirm the prompt.
3. Choose your profile if asked. The title bar will show (Safe Mode).

Microsoft's own guide to classic Outlook freezing notes that simply starting in safe mode once, then closing and reopening normally, clears some "Processing" hangs on its own. If Outlook is stable in safe mode but not normally, go to Fix 3. If it still hangs in safe mode, skip to Fix 4.

Fix 3: Disable COM add-ins one at a time

Add-ins from PDF tools, CRM connectors, meeting apps, antivirus suites and old Skype for Business installs are the usual suspects. One faulty add-in can stall Outlook at startup.

1. In Outlook (safe mode is fine), go to File > Options > Add-ins.
2. Next to Manage, choose COM Add-ins and click Go.
3. Untick everything and click OK. Restart Outlook normally.
4. If it now works, re-enable add-ins one at a time, restarting after each, until the hang returns. Leave that add-in off, then update or remove it.

Also check File > Options > Add-ins for anything listed under Disabled Application Add-ins. Outlook disables slow add-ins itself and tells you so with a yellow bar. That's a useful clue to which one is causing trouble.

Fix 4: Reset the navigation pane and views

The navigation pane settings file can become corrupted, which causes hangs at startup or errors such as "Cannot start Microsoft Outlook. Cannot open the Outlook window." Close Outlook, press Windows + R and run outlook.exe /resetnavpane. This removes custom favourites and pane layout but nothing else. If a particular folder freezes when opened, outlook.exe /cleanviews restores the default views. Note that it also removes any custom views you've created.

Fix 5: Run Microsoft's automated troubleshooters

The old Microsoft Support and Recovery Assistant (SaRA) has been retired. Its Outlook diagnostics now live in the Windows Get Help app. Microsoft keeps a list of classic Outlook troubleshooters that open the right scenario directly, including ones for Outlook that won't start or stops responding. They check for known issues, problem add-ins and profile problems, and they're worth running before the heavier fixes below.

Fix 6: Repair or rebuild the Outlook data file

Outlook keeps mail in a data file. Microsoft 365, Exchange, Outlook.com and IMAP accounts use an .ost cache; POP accounts and archives use a .pst. You can see which files your profile uses under File > Account Settings > Account Settings > Data Files.

Repair a .pst with the Inbox Repair Tool (SCANPST.EXE)

1. Close Outlook and copy the .pst somewhere safe first.
2. Open SCANPST.EXE. For current Click-to-Run versions (Microsoft 365, 2016–2024) it's in C:\Program Files\Microsoft Office\root\Office16, or the same path under Program Files (x86) for 32-bit Office.
3. Browse to the .pst, click Start, then Repair if errors are found. Run it again until it reports no errors. Large files can need two or three passes.

Microsoft's data file repair article covers the tool in detail, including how to recover items from the backup it creates.

Rebuild an .ost (Microsoft 365 and Exchange)

For server-based accounts, repairing the .ost is rarely worth it. Close Outlook, open %localappdata%\Microsoft\Outlook in File Explorer, and rename the .ost (for example to name.ost.old). When you reopen Outlook it downloads a fresh copy from the server. The only things you could lose are items that never synced, such as drafts created offline, so check those first. On a large mailbox the first sync can take a while. That's normal.

Fix 7: Repair the Office installation

1. Close all Office apps.
2. In Windows 11 go to Settings > Apps > Installed apps, find your Microsoft 365 or Office entry, click the … menu and choose Modify. In Windows 10, use Control Panel > Programs and Features > Change.
3. Run Quick Repair first. If Outlook still hangs, run Online Repair, which reinstalls Office and needs an internet connection.

After an Online Repair you may need to sign in or re-enter activation details. If Office reports itself as unlicensed afterwards, our Unlicensed Product fix guide walks through the cause.

Fix 8: Create a new Outlook profile

If Outlook hangs on "Loading Profile" even in safe mode, the profile itself is often corrupt. A new profile doesn't delete mail: server accounts resync, and .pst files can be reattached.

1. Close Outlook. Open Control Panel, switch View by to Small icons and open Mail (Microsoft Outlook).
2. Click Show Profiles > Add, give it a name, and sign in to your account.
3. Select Prompt for a profile to be used so you can switch back if needed, then start Outlook with the new profile.
4. Once it's working, set it to Always use this profile and remove the old one.

While you're here, check that OUTLOOK.EXE isn't set to run in compatibility mode. Right-click the file in the Office16 folder, open Properties > Compatibility, and make sure nothing is ticked. Compatibility mode is a known cause of the "Loading Profile" hang.

Fix 9: Reduce mailbox and data file size

Outlook slows noticeably as data files grow very large, and folders holding tens of thousands of items are slow to render. A few practical changes:

• Limit the cached mailbox: File > Account Settings > Account Settings, select the account, click Change, and reduce Download email for the past to 6 or 12 months. Older mail stays on the server and is still searchable.
• Split huge folders (especially Inbox and Sent Items) into yearly subfolders.
• Empty Deleted Items and Junk, and use File > Tools > Mailbox Cleanup to find large items.
• Don't keep .pst files on network shares or in synced cloud folders. Outlook doesn't support that, and it causes hangs and corruption.

Fix 10: Updates, credentials and security software

• Update Office: File > Office Account > Update Options > Update Now, then install pending Windows updates.
• Clear stored credentials: open Credential Manager > Windows Credentials and remove entries starting with MicrosoftOffice16 or containing Outlook, then sign in again. Endless sign-in loops often look like a hang.
• Security software: email-scanning plug-ins from third-party antivirus are a frequent cause of freezes when opening or sending mail. Update the product or turn off its Outlook integration.
• Clean boot: if nothing else helps, a clean boot (via msconfig) shows whether a background program is interfering.

What if you're using the new Outlook?

The new Outlook for Windows is a different app built on web technology. It doesn't use COM add-ins, .pst-based profiles or SCANPST, so most of the fixes above don't apply. If it freezes, end it in Task Manager and reopen it. If it keeps happening, uninstall it from the Start menu and reinstall it from the Microsoft Store. If you depend on COM add-ins, .pst archives or offline access to large mailboxes, classic Outlook remains the better fit, and it's included with perpetual Office editions such as Office Home & Business 2024 and Professional Plus 2024. Our Office 2024 vs Microsoft 365 comparison explains how the two licensing models differ.

Outlook startup switches at a glance

All of these are typed into the Run box (Windows + R) with Outlook closed. They affect only classic Outlook.

Command	What it does	What you lose
outlook.exe /safe	Starts without add-ins and customisations	Nothing, it's temporary
outlook.exe /resetnavpane	Rebuilds the folder/navigation pane	Favourites and pane customisations
outlook.exe /cleanviews	Restores default folder views	Custom views and column layouts
outlook.exe /profiles	Asks which profile to open	Nothing

A tip from experience: change one thing at a time and restart Outlook between steps. If you reset the nav pane, disable add-ins and rebuild the .ost in one go, you won't know which change fixed it, and the problem will come back the next time that add-in updates.

Frequently asked questions

Why is Outlook stuck on "Loading Profile"?

The usual causes are a faulty add-in, a corrupt profile, compatibility mode on OUTLOOK.EXE, or a credential prompt hidden behind the splash screen. Try safe mode first, then a new profile.

Will creating a new Outlook profile delete my emails?

No. Microsoft 365, Exchange, Outlook.com and IMAP mail is stored on the server and resyncs. Local .pst files remain on disk and can be reopened with File > Open & Export > Open Outlook Data File.

Where is SCANPST.EXE in Office 2021 or 2024?

In C:\Program Files\Microsoft Office\root\Office16 for 64-bit Office, or under Program Files (x86) for 32-bit installs.

Is it safe to delete the .ost file?

For server-based accounts, yes. Renaming is safer still. Outlook rebuilds it from the server. Never delete a .pst, which may be the only copy of its contents.

How do I start Outlook in safe mode in Windows 11?

Press Windows + R, type outlook.exe /safe and press Enter, or hold Ctrl while opening Outlook.

Should I reinstall Office if Outlook keeps freezing?

Only after an Online Repair and a new profile have failed. Reinstalling rarely fixes problems caused by add-ins or data files, because both survive a reinstall.

Our recommendation

Work through the list in order: safe mode, add-ins, nav pane, repair, data file, profile. You'll rarely need to go past Fix 8. If your copy of Office is very old and out of support, or you need a fresh, properly licensed install with classic Outlook, Office Home & Business 2024 includes Outlook alongside Word, Excel and PowerPoint, and our installation guide takes you from download to activation.

View Office Home & Business 2024

Related reading

Resource	Why read it
Office "Unlicensed Product" fix	If activation breaks after a repair
Office 2024 vs Microsoft 365	Choose between perpetual and subscription Office
Office Home & Business 2024 install guide	Clean install and activation, step by step