Installation on windows xp

It seems Opto is blocking the installion of its software on a computer with XP operating system. Is this a rare occurrence that I need to change something on my computer or is this on Opto’s end. We have a lot of older computers that we use to operate equipment of various kinds that cannot connect to the internet, but are perfectly good for operating facility equipment, lab equipment, etc. Is there a workaround to this or a solution to install Opto PAC Project software on older operating systems? The PAC Project software is the latest free version on Opto’s website.

Thanks for the help.

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Hi, @rpburnet—Yep, you’re correct that current versions of PAC Project no longer run on Windows XP. The only workaround I know of (besides upgrading to Windows Vista or higher) is to use PAC Project R9.4 (the last version that supports Windows XP). You can get it from the Opto 22 Archives FTP site:

In 2016, Opto 22 announced the decision to stop supporting XP and Windows 2000. The reason was to avoid potential system errors that can happen when running software developed with current technologies on an unsupported operating system. (Microsoft stopped supporting XP in April 2014.)

Supported OSs are listed on PAC Project’s Downloads page ( and also on the Specification tab on the Product page (

Opto 22 Tech Writer

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Thank you for your help and explanation.

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