How to Open RPMSG Files: Step-By-Step Guide

RPMSG files are email messages created by Microsoft Outlook. You can open them by dragging them into Outlook, using the Outlook file recovery feature, or converting them with third-party tools like CloudMounter or Stellar. If you don’t have Outlook, free alternatives like Mozilla Thunderbird or online converters work well.

What is RPMSG File?

An RPMSG file is an Outlook-specific email format. When you see a file ending in .RPMSG, it’s essentially a protected or restricted email message. These files often contain sensitive information because Outlook encrypts them with Information Rights Management (IRM) protection.

The main reason RPMSG files exist is security. Microsoft created this format to protect emails that have restrictions on copying, printing, or forwarding. If someone sends you a restricted email, Outlook saves it in RPMSG format instead of the standard MSG format.

Understanding this difference matters because it affects how you can open these files. A basic MSG file opens in many programs. An RPMSG file needs specific tools or Outlook itself.

Method 1: Opening RPMSG Files in Microsoft Outlook

This is the simplest method if you have Outlook installed.

Step-by-step process

Open Microsoft Outlook on your computer. Make sure you’re signed in with the same account that received the email.

Go to File menu and select Open and Export. Then choose Open Outlook Data File.

Navigate to your RPMSG file on your computer. Select it and click Open.

The file will appear in Outlook as a folder. Find the email message inside and double-click to read it.

The email opens with all formatting and attachments intact. This is the most reliable way to access restricted emails.

Important note about permissions

When you open an RPMSG file in Outlook, the restrictions apply to your viewing. You might not be able to forward the email, copy text, or save attachments depending on how the sender configured it. This is intentional. The sender chose these restrictions for security reasons.

Method 2: Using Mozilla Thunderbird

Thunderbird is a free email client that works well with many email formats. It can open some RPMSG files, though results vary depending on the protection level.

How to do it

Download and install Mozilla Thunderbird from mozilla.org.

Import your RPMSG file into Thunderbird through the Import function found in the Tools menu.

Select Import Mail and choose from file option.

Browse for your RPMSG file and follow the prompts.

Thunderbird converts the file to its format and makes it readable. Keep in mind that encryption protections might prevent full access to the content.

Method 3: Converting RPMSG to MSG Format

Converting RPMSG to MSG gives you more flexibility. MSG files open in more programs than RPMSG files.

CloudMounter conversion method

CloudMounter is a cloud storage tool that also handles email file conversions. You can mount your RPMSG file as a folder and access its contents.

Download CloudMounter and install it on your computer.

Open the application and select RPMSG file from your system.

The tool extracts readable content into a temporary location.

Copy the extracted data to your desired format.

This method works best when encryption is minimal. Heavily restricted files might still resist conversion.

Using Stellar Mail Recovery

Stellar Mail Recovery specializes in recovering and converting email files. It handles RPMSG conversion smoothly.

Install Stellar Mail Recovery on your computer.

Launch the application and select RPMSG File Recovery.

Choose your RPMSG file from your computer.

Click Start to begin the recovery process.

Select the MSG format as output and complete the conversion.

The resulting MSG file opens in most email clients.

Method 4: Online RPMSG Converters

Web-based tools offer a quick solution when you don’t want to install software.

How they work

Visit a converter website like CloudConvert or Zamzar.

Upload your RPMSG file to the site.

Select MSG as the output format.

Download the converted file to your computer.

This method works fast for basic conversions. However, security-conscious users should avoid uploading sensitive emails to public websites.

Privacy consideration

Online converters store files temporarily on their servers. If the email contains confidential information, local conversion tools are safer. Check the website’s privacy policy before uploading.

Method 5: Checking Your Email Client Settings

Sometimes RPMSG files appear because your email client settings need adjustment.

Gmail integration

If you use Gmail with IMAP, properly configured accounts download emails as MSG instead of RPMSG. Check your Outlook settings.

Go to File > Options > Advanced.

Under Import and Export, verify your default email format is set correctly.

Re-download emails from Gmail to avoid RPMSG conversion.

Outlook settings

Open Outlook and navigate to the account where you received the email.

Check account properties and ensure encryption settings align with your needs.

Disable Information Rights Management if you don’t require restricted emails.

Opening Methods

Method	Ease	Cost	File Access	Speed
Outlook Desktop	Very Easy	Paid	Full	Instant
Thunderbird	Easy	Free	Partial	Quick
CloudMounter	Moderate	Free	Limited	Moderate
Stellar Recovery	Moderate	Paid	Good	Moderate
Online Converter	Very Easy	Free	Variable	Very Fast

Why You Received RPMSG Files

Understanding the source of RPMSG files helps you manage them better.

Restricted email policies

Companies often use restricted emails for sensitive documents. HR departments, legal teams, and finance departments frequently send RPMSG files to prevent unauthorized sharing.

Outlook encryption settings

The sender might have Information Rights Management enabled by default. Every email they send becomes restricted, creating RPMSG files for recipients.

Third-party integrations

Some business software integrates with Outlook and automatically creates restricted emails. Marketing automation tools, customer relationship management systems, and data security software often do this.

Troubleshooting Common Problems

File won’t open in Outlook

Ensure you’re using the same Outlook account that received the email. Sign out and sign back in if needed.

The file might be corrupted. Try opening it on a different computer with Outlook installed.

Check if your Outlook version is current. Old versions struggle with newer encryption standards.

Conversion fails repeatedly

The file might be severely corrupted. Download it again from your email if possible.

Try a different conversion tool. Some tools handle specific RPMSG variants better than others.

Temporarily disable antivirus software, as it sometimes blocks file conversions.

Permission restrictions prevent viewing

Contact the original sender and ask them to resend without restrictions.

Ask the sender to use your organization’s rights management to adjust permissions.

Request the sender forward the email normally instead of as a restricted message.

Best Practices for Managing RPMSG Files

Create a dedicated folder on your computer for RPMSG files. This keeps them organized and easier to locate.

Convert important RPMSG files to MSG format immediately after receiving them. This prevents future compatibility issues.

Back up converted files in multiple locations. RPMSG files sometimes become inaccessible if Outlook updates occur.

Document which emails contain restricted content. This helps you remember why certain messages have limitations.

Summary

Opening RPMSG files is straightforward once you understand what they are. Microsoft Outlook offers the most reliable method, but free alternatives like Thunderbird work in many situations. For users without Outlook, conversion tools provide practical solutions.

The fastest approach depends on your setup. If Outlook is installed, use it directly. If not, online converters offer speed without installation. For batch processing or repeated conversion needs, dedicated tools like Stellar work best.

RPMSG files exist for security reasons. While they sometimes seem inconvenient, they protect sensitive business information. Respecting the restrictions placed on these emails maintains security across organizations.

Start with Outlook if available. Try Thunderbird next if Outlook isn’t installed. Use conversion tools as a last resort when other methods fail. Most RPMSG files open successfully with one of these methods.

Frequently Asked Questions

Can I open RPMSG files on Mac?

Yes, but options are limited. Outlook for Mac opens RPMSG files. Thunderbird also works on macOS. Online converters work on any operating system.

Are RPMSG files safe to open?

Yes, they’re safe. The restriction is about protecting content, not about viruses. RPMSG files from legitimate sources present no safety risk. Always verify the sender’s identity before opening any email attachment.

Can I print content from RPMSG files?

It depends on the sender’s restrictions. Some RPMSG files allow printing. Others explicitly block it. The sender controls these permissions when they send the restricted email.

How do I prevent receiving RPMSG files?

You can’t prevent others from sending them. However, you can request that frequent senders disable Information Rights Management. This causes their emails to arrive as normal MSG files instead.

Will converting RPMSG to MSG remove restrictions?

Not always. Some restrictions embed themselves in the email content. However, conversion often bypasses technical restrictions, allowing you to access content that would otherwise be blocked.