How Do I Fix “Outlook has exhausted all shared resources please close all messaging applications” within Few Seconds?

You might come across the error message: “The set of folders cannot be opened. Outlook has exhausted all shared resources please close all messaging applications” when launching Outlook or while sending and receiving mails. This issue typically arises when your system runs low on available resources, preventing Outlook from functioning properly.

Here’s a real user’s experience illustrating the problem:

“I’m using Windows 10 and every few days, Outlook 365 Classic won’t open. Instead, I get this error: [The set of folders cannot be opened. Outlook has exhausted all shared resources please close all messaging applications and restart Outlook (e.g., Skype for Business).] Logging out and back into Windows temporarily fixes it, but the issue returns. I tried checking the Registry Editor under HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\PST to adjust the PST file size limit, but the PST folder isn’t there. I’m stuck and don’t know what to do next.”

When this error appears, Microsoft Outlook may refuse to open or crash unexpectedly. Sometimes, you may be able to access one mailbox, but attempting to open others triggers the error. This can disrupt your email workflow and cause delays in communication.

In this blog, we’ll dive into the common causes behind this error and provide effective solutions to fix the “Outlook has exhausted all shared resources” issue so you can get back to smooth email management.

Common Reasons behind the Outlook Error: “Outlook Has Exhausted All Shared Resources Please Close All Messaging Applications”

• Insufficient RAM on the computer running Outlook.
• Numerous background processes consuming system resources.
• Other messaging apps like Teams, Zoom, or Skype using shared resources simultaneously.
• A corrupted Outlook profile.
• Faulty or incompatible add-ins disrupting Outlook’s performance.
• Using an outdated version of Outlook.
• Multiple large PST files loaded into your Outlook account.
• A damaged navigation pane (folder list).
• Corrupted Outlook PST files.
• Having too many email accounts configured in MS Outlook.

How to Fix the Error “Outlook Has Exhausted All Shared Resources, Please Close All Messaging Applications”

If you encounter this error, try the following solutions to get Outlook running smoothly again:

Way 1: Close Other Messaging Applications

Since multiple applications share system resources, this error often appears when other messaging apps are running simultaneously. To free up resources, close any unnecessary messaging programs by following these steps:

• Press Ctrl + Shift + Esc to open Task Manager.
• Under the Processes tab, locate messaging apps like Teams, Skype, or Zoom.
• Select each app and click End Task to close it.
• Once done, restart your computer and launch Outlook again.

Way 2: Reset the Navigation Pane

A corrupted navigation pane can prevent Outlook from opening folders properly, triggering this error. Resetting it can help:

• Close Outlook if it’s open.
• Press Windows + R to open the Run dialog box.
• Type Outlook.exe /resetnavpane and hit Enter or tick OK.
• Outlook will start with a fresh navigation pane, potentially resolving the issue.

Way 3: Create a New Outlook Profile

A damaged Outlook profile can cause this error. Creating a new profile often fixes the problem:

• Open Control Panel, then go to User Accounts > Mail.
• In the Mail Setup – Outlook window, click Show Profiles, then select Add.
• Enter a name for the new profile.
• In the Auto Account Setup, enter your Name, Email Address, and Password, then click Next.
• Once finished, click Finish.
• Back in the Mail dialog, under when starting Microsoft Outlook, use this profile, choose Prompt for a profile to be used and click OK.
• Restart Outlook.
• When prompted, select your newly created profile from the dropdown and click OK.

Way 4: Limit the Number of PST Files

Having multiple large PST files linked to your Outlook can overload shared resources and cause this error. To resolve this, remove any unnecessary PST files or split large PSTs into smaller ones. Follow these steps to delete unwanted PST files:

• Open Outlook.
• Navigate to File > Account Settings > Account Settings.
• Click on the Data Files tab to view all connected PST files.
• Select the PST files you no longer need and click Remove.
• Alternatively, consider archiving old emails into separate backup PST files to reduce the size.

Way 5: Manage and Remove Unused Accounts

Too many email accounts configured in Outlook can strain system resources. Removing unused accounts can help:

• Go to File > Account Settings > Account Settings.
• Under the Email tab, review all your configured accounts.
• Select and remove any accounts that you no longer use.

Way 6: Modify Cache Size Settings to Fix Outlook Resource Error

Many users on the Microsoft Community forum have reported resolving the “Outlook has exhausted all shared resources” error by tweaking the cache size settings for PST files. You can achieve this by adding a registry key that reduces Outlook’s memory usage. Follow these steps:

• Open the Registry Editor by typing Regedit in the Run dialog (press Windows + R) and clicking OK.
• Navigate to the Outlook registry path for your version. For example, for Outlook 2016, go to:
  HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\16.0\Outlook
• Right-click on Outlook, select New > Key, and name it PST.
• Right-click the newly created PST key, choose New > DWORD (32-bit) Value.
• Name this value UseLegacyCacheSize.
• Double-click it, set the value data to 1, and press Enter twice to save.

Additionally, you can increase the maximum size allowed for Outlook data files (PST) by adding the MaxFileSize or MaxLargeFileSize DWORD values in the same registry path. This can help if you frequently work with large PST files.

Way 7: Repair Your Corrupt PST File

Outlook relies heavily on PST files to manage your email data. When a PST file becomes corrupted, Outlook may repeatedly try to access it, which can drain system resources and trigger errors like “Outlook has exhausted all shared resources.” While Microsoft’s built-in ScanPST tool can fix minor PST corruption, it often struggles with large, severely damaged, or encrypted PST files and may freeze or fail to repair them.

To overcome these limitations, you can use specialized PST repair software that efficiently restores corrupted PST files without any data loss.

BitData Migration PST Converter is a powerful tool to repair PST files from any Outlook version, regardless of their size or level of corruption. After repairing, it allows you to preview mailbox contents and export them to multiple formats, including EML, MSG, MBOX, RTF, PDF, CSV, ICS, vCard, MHT, HTML, Gmail, Yahoo, Hosted Exchange Server, Windows Live Mail, Zimbra, Lotus Notes, Office 365, and more.

Final Lines

We’ve discussed the common causes of the “Outlook has exhausted all shared resources, please close all messaging applications” error and several effective solutions to fix it. If PST file corruption is the root cause, relying on Outlook Converter can ensure a safe and complete recovery of your emails and data without any loss, helping restore Outlook’s smooth operation.