Solution:

1. Open the registry editor.
2. Go to: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall
3. Right-click on the Uninstall folder and select: Find…
4. In the Find what field, paste the GUID that you copied from the list below.
5. Click Find Next. When the key is found, the folder name will be the same as the GUID from the list below.
6. Right-click the GUID folder, choose Delete, and confirm the deletion.
7. Go to: HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall
8. Right-click the folder with the name of the product you are trying to install, choose Delete, and confirm the deletion.
9. Re-run the installation. No previous installation should be detected.

We are aware of the issues and are actively investigating it.

The following examples are from versions X9 to the latest release of Mastercam. The GUID may be different if you were trying to install a Technical Preview or Beta release.

For Mastercam X9:

• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{9869D25D-C67E-4282-B4D0-DB6218BC94D5}
• HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall\Mastercam X9

For Mastercam 2017:

• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{65A2ED1B-68D3-41B6-B274-0ED36CE9BC67}
• HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall\Mastercam 2017

For Mastercam 2018:

• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{B66E2B7B-6BD8-49BD-815C-48BF88D24406}
• HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall\Mastercam 2018

For Mastercam 2019:

• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{34B8BDB8-85A4-4E03-815B-98EC6A520637}
• HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall\Mastercam 2019

For Mastercam 2020:

• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{DEC00F01-E8BD-4D06-B531-ECD782BA6FF2}
• HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall\Mastercam 2020

For Mastercam 2021:

• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{41DEF8DB-31EF-4207-A3FC-B8FF8B8455D4}
• HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall\Mastercam 2021

For Mastercam 2022:

• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{E5A17A38-67C1-4769-B47E-247D8762FB1E}
• HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall\Mastercam 2022

For Mastercam 2023:

• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{D06A6FEB-3BAE-4C61-933D-F2C91DD37079}
• HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall\Mastercam 2023

For Mastercam 2024:

• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{FF11CF88-5828-4326-91EC-0122BF3EB207}
• HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall\Mastercam 2024

For Mastercam X9 Demo-HLE:

• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{6BF7AB53-16D0-49B7-8B68-3DFF59476FDB}
• HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall\Mastercam X9 Demo-HLE
  

For Mastercam 2017 Demo-HLE:

• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{D9DC9819-E952-43AD-994C-230728C685E2}
• HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall\Mastercam 2017 Demo-HLE

For Mastercam 2018 Demo-HLE:

• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{5EC758A8-D4F0-4073-B355-64D117CD47B6}
• HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall\Mastercam 2018 Demo-HLE

For Mastercam 2019 Demo-HLE:

• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{82D7EABD-F5A5-4B19-82E9-7AF18610CFF6}
• HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall\Mastercam 2019 Demo-HLE

For Mastercam 2020 Demo-HLE:

• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{BB37FC3B-A6AF-4F9C-A0A5-8112E0560F6F}
• HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall\Mastercam 2020 Demo-HLE

For Mastercam 2021 Demo-HLE:

• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{BF3944AD-54F5-4AAA-97D1-4B0237C85CF1}
• HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall\Mastercam 2021 Demo-HLE

For Mastercam 2022 Demo-HLE (now the same as the standard Mastercam 2022 install):

• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{E5A17A38-67C1-4769-B47E-247D8762FB1E}
• HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall\Mastercam 2022

For Mastercam 2023 Demo-HLE (now the same as the standard Mastercam 2023 install):

• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{D06A6FEB-3BAE-4C61-933D-F2C91DD37079}
• HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall\Mastercam 2023

If you are unable to find these registry keys, you can try using the Microsoft Install/Uninstall Troubleshooter, please contact a technical support rep for it.

Click here to get it: https://support.microsoft.com/en-us/help/17588/windows-fix-problems-that-block-programs-being-installed-or-removed

Choose the Uninstall option when running it, when the list of program appears, choose “Not Listed” and paste the appropriate GUID (including curly brackets) to proceed.

If this still doesn’t work, you can try installing the program directly from the MSI file.