Resolve “Unable to Open Outlook Attachments” Issue

Summary: Are you a daily users who work with Microsoft Outlook? There are instances when you experience issues while trying to access some email attachments in MS Outlook 2019 / 2016 / 2013 / 2010 and so on. This issue may come in the form of an error message such as Unable to open Outlook attachments which will prevent you from opening the attached files. So, with the help of this blog post, we are going to understand the reasons, and follow simplify methods to resolve this issue.

Why Users Can’t Open Attachments in Outlook – Common Causes

When you are facing the issue unable to open Outlook attachments, there may be a number of reasons behind it. Below we have listed the most common ones for you.

• Temporary Internet file folder has reached its storage limit.
• Also, the user may not have sufficient permission to access the temp Internet files on the server.
• The error associated with the temp folder is as follows:

Can't Open Outlook Attachment

• One more case related to temp file folder is that after a certain time-period, Outlook stops saving temporary files with the same name.
• In Outlook, Default Security Protocols also intervenes by preventing user access to any potentially harmful attachment.
• Some extensions such as .exe, .url etc. are deemed suspicious and thus blocked by Outlook 2019 / 2016 / 2013.
• The PST data file is corrupt or damaged which will eventually restrict you from opening any attachments stored in it.
• Repair Outlook PST files before trying to access your Outlook attachments.

Resolve “Unable to Open Outlook Attachments” Issue – Manual Methods

There are various manual solution which you can try to fix the desired error. For those, who deals with Outlook application on daily basis.

#1. For Temporary Corrupted Folders Related Cause

Attachments may fail to open due to the corruption in the temp folder. Follow the steps to delete those folders:

• Open Run dialog box by hitting Windows+R command in your system
• Type regedit.exe and hit enter to open the Registry Editor.
• Go to the menu and select Edit >> Find to open the Find dialog box.
• Here, enter OutlookSecureTempFolder and click on Find Next button.
• In the search results, note the folder location associated with OutlookSecureTempFolder.

• Exit the Registry editor and open Windows Explorer
• Locate and open the same folder location which you noted down previously
• Delete all files present in this folder and close the Explorer

Now, restart MS Outlook 2019 / 2016 / 2013 / 2010 / 2007 / 2003 and check if you can access your attachment or not. If yes, then the issue is resolved. But if you are still unable to open Outlook attachments, go for the next solution.

#2. To Unblock Blocked attachments Due to Outlook Security Protocol

Before performing the following steps, make sure that MS Outlook is closed.

• Hit Windows+R button to open the Run dialog box.
• Type regedit.exe and press Enter key to open Registry Editor.
• Next, hit Ctrl+F, and type OutlookSecureTempFolder and click Find Next button.
• After that, go to Edit >> New >> String Value and name it Level1Remove.

• Now, double click on this value and enter the file extension that you want to unblock such as: .exe. For multiple extension, type .exe; .url, .bak.

• This is the last step where you  need to click Ok and exit the registry editor.
• Now, open the Outlook application and you can now open the previously blocked attachments.

 #3. Temporarily Disable Antivirus (For Testing Only)

Attachments are also improperly blocked by these antivirus tools at times. Here, are the steps to do it:

• Firstly, disable antivirus temporarily.
• Next, open Outlook and test attachments whether it is working or not.
• For that, open any attachments to see.
• Configure AntiVirus settings so that it whitelists Outlook’s attachments.

Take Note: Remember to enable antivirus after the test.

#4. Update Microsoft Outlook

Using older software means there might be an OS that is not supported by popular browser. By, updating you might fix the unable to open Outlook attachments error.

• Launch Outlook > Click on File > Office Account > Update Options > Update Now.
• Restart Outlook after update to see any changes.

#5. Repair Your Outlook Profile

The most likely cause of this issue is a damaged Outlook profile. Follow these quick steps to repair:

• Go to this given path: Control Panel > Mail > Click On Show Profiles.
• Choose Profile > Delete (backup first) or Add New Profile.
• Restart Outlook and test.

#6. Use Outlook Web App (OWA)

If none of this works, open the Outlook Web version and see the attachments.

• Log into Outlook on the Web
• Find the email and attempt to access the attachment.

That is one of the methods to figure out if the problem is with a desktop app or not.

#7. Check Default Program Association

If Outlook is unable to open certain files, verify that there isn’t a default application assigned:

1. Right click on a file with the extension e.g. PDF.
2. Click on Open with > Choose another app.
3. Select the right app and tick always use this app
4. Now, you can try re opening the file in Outlook.

#8. Solution if the cause is PST Corruption

Even after implementing the above methods, you still are unable to open Outlook attachments, then the most probable cause is corrupt PST file. The two ways to deal with it are explained as follows:

Use Automated Software

What to do when nothing works? Stop using Outlook altogether? Well no, you don’t need to take such drastic measures. Because we have a safe and result-oriented approach in the form of SysTools Outlook Recovery right here for you. It is by any means the BEST Software to repair Outlook PST corruption without ScanPST and also it will repair any level of corruption from PST file without fail regardless of Outlook version. Be it any issue such as ‘unable to open Outlook attachments’, as long as it is related to data file corruption, this tool can solve them all. The software can scan Outlook 2019, 2016, 2013, 2010, 2007, 2003, 2002, 2000 data file.

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Use Inbox Repair Tool (ScanPST.exe)

It is an inbuilt tool provided by Microsoft to rectify minor corruption issues in Outlook 2019, 2016, 2013, 2010.

• To use it, simply Run scanpst.exe in the Run dialog box.
• Browse the concerned Outlook PST file and start the process.
• It will repair the data file of any header errors and other minor issues.
• Being a free utility, it certainly is worth trying.

However, this tool is utterly useless in cases of major corruption. It is also noticed that it is incompetent when there is an issue with contacts, calendars, tasks, and attachments. In addition, data loss issues have often been associated with this inbox repair tool.

Difference table – Manual Vs Automated Approach

This is the section where you will see key difference between both these methods. Have a look into it:

Aspect	Manual Methods	Automated Method
Complexity	Requires technical knowledge	Easy to use interface, no technical skills required
Time Required	Time-consuming, multiple try needed	Fast – fix or extract attachments in a few clicks
Accuracy	May not resolve issues like PST corruption	Repairs corruption and restores full attachment access
Data Safety	Risk of data loss or missteps during registry or profile	100% secure – maintains original data structure
Scope of Issue Resolution	Works for surface-level issues only	Fixes all attachment related issues including due to PST corruption
Usability	Not user-friendly for non-tech users	Designed for both beginners and professionals
Success Rate	Depends on the exact cause, not always effective	High success rate across Outlook versions and file types

Final Words

If you are unable to open Outlook attachments, there could be various reasons behind it. In this article, we discussed all those reasons and gave possible solutions for each of them for Outlook 2019, 2016, 2013, 2010, 2007, 2003, 2000. A variety of manual solutions are provided to rectify this issue. However, in case everything fails, we also included an out of the box automated solution. With this tool, solving any PST file corruption or related problems is now an easy, safe and quick process with no data loss issue whatsoever.