Have you ever tried to open a Microsoft Excel document received in Outlook and encountered the error message below?
“Microsoft Excel cannot open or save any more documents because there is not enough available memory or disk space.
To make more memory available, close workbooks or programs you no longer need.
To free disk space, delete files you no longer need from the disk you are saving to.”
Screen Capture:

When you receive this error like I have, you probably tried a few of these fixes below but were left without a solution:
- You most likely opened Task Manager to view your current system resources only to find plenty of memory available, plenty of CPU available, and plenty of disk space available. And when I say plenty, I mean at least 60% of these resources are available.
- You may have done a Repair under the Windows 10/Settings/Apps area on the Office 365 installation. The repair may take 15 minutes or longer for the system to complete. However, this does not correct the issue.
- The actions above are normal research and corrective actions to take, but in this case we are no closer to a solution.
I have encountered into this issue a few times and finally figured out a solution. To start, the error message does not align to the actual issue. The issue is really a security related prompt with a relatively easy fix. I say relatively easy fix because as the instructions below will indicate, it is a security related check box that needs disabled. However, you must understand the implications of this action.
Below are steps to correct this issue followed by a section about understanding the security related concerns of following them.
Solution Steps:
The solution is to uncheck a security setting from within Microsoft Excel that is enabled by default to protect your system from malicious files received through Outlook.
Note: Remember to re-enable this setting once you have successfully opened your file.
- In Microsoft Excel, click on File

2. In the left index area of Excel, at the bottom of the screen is an option called Options. Click on it.


3. In the Excel Options screen that appears, click Trust Options on the lower left of the screen.

4. Then click Trust Center Settings…

5. In the Trust Center settings, click Protected View on the left.

6. By default, all three areas are selected. To correct the issue, de-select the option “Enable Protected View for Outlook Attachments.”

7. Select OK several times to save the settings.
8. Attempt to open the document again and you will now be prompted to verify you want to open this document and that you trust the sender. The document should now open correctly.
9. Important: Once your file is opened, make sure you then re-enable this setting as it is key to help protect your system!
Understanding Important Security Concerns
It is important to understand that this setting is in place by default to protect you as the user from opening a file that may be malicious. Even if you know who the sender of the file is, there is no way to tell if that person’s email or system has been infected. Prior to opening this file please consider taking the following steps to protect yourself.
- Verify you have the latest Microsoft Windows updates installed by going to Settings and Windows Update.
- Verify you have an active antivirus agent on your system. Windows 10 now comes with Microsoft Defender at no cost and is rated “the best antivirus tool for Windows 10 PCs.” Make sure it is enabled by opening the Microsoft Security Center on your laptop or desktop.
- Submit the file for viruses and malicious activity, prior to opening it. First, save the file to your desktop. Secondly, submit it to one of these reputable services to be scanned. If this is a document with sensitive information, I do not recommend submitting this file to any website for scanning. In this case, seek professional technical assistance.
- TrendMicro file scanning online service
- VirusTotal analysis
Brilliant thankyou so much. In our case it was actuallly files from “potentially unsafe locations” – which were actually our own internal file network!
Thanks so much. You saved my day
Your solution worked flawlessly.
Thank you, this worked for me..
As usual microsoft has an error message that has nothing to do with the actual bug. In my case, it was “potentially unsafe locations” that needed to be unchecked. Perhaps you can uncheck each one one-by-one or just uncheck all 3 options to see quickly if this is the problem.
File opened without problems. Thanks so much for a useful guide.
I had similar error when creating new excel document.
After correcting key in registry, error was gone.
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\User Shell Folders
I’ve set Cache to :
C:\Windows\Temp
Thanks a lot. – You made my day.
Thank you so much…… It Really Works
Despite the fact that this did not work for me, it gave me the idea to launch Excel with “run as administrator,” which was successful. Thank you.