How to upgrade the Windows 7 RC to RTM (final release)

Upgrading Windows 7 RC (Release Candidate) to RTM (Release to Manufacturing) was a common question in 2009. Because RC builds were designed to expire, moving the final release was strongly recommended. 

Microsoft provided an official recommended method for upgrading, which required a clean installation.

Official recommended method 

Microsoft required users to perform a custom install rather than a direct upgrade. The steps included:

• Backing up all important files
• Booting the Windows 7 RTM from a USB or DVD
• Choosing advanced installation
• Installing over the existing RC partition
• Reinstalling programs and restoring personal files

This method ensured the most stable and reliable transition to the final version. 

Unofficial workaround

However, there was a workaround that allowed you to upgrade without wiping everything. This method was unsupported by Microsoft and could cause instability or leftover RC files, so the custom installation was preferred. 

1. Insert the Windows 7 RTM DVD

2. Copy all files from the DVD to a folder on your hard drive

3. Navigate to:

sources/cversion.ini 

4. Open in Notepad:

cversion.ini 

5. Change:

MinClient=7233.0 

to 

MinClient=7100.0

1. 7100 was the RC build number 

6. Save file 

7. Run: 

setup.exe 

from the copied folder

8. Choose Upgrade instead of custom

This method allowed the installer to proceed with an in-place upgrade from RC to RTM.

Modern context

As of January 2020, Windows 7 is no longer supported by Microsoft and no longer receives security updates. Running Windows 7 on internet-connected systems is not recommended. 

Users should upgrade to a supported operating system such as:

• Windows 10
• Windows 11

Upgrading from Windows 7 RC to RTM was an important step for users in 2009 who wanted to move from a temporary test build to a fully supported operating system. Today, Windows 7 is a part of computing history, and if you’re revisiting it for testing or archival purposes, understanding the proper upgrade path helps preserve functionality and stability.