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I'm running out of disk space and could not install version 4 of the dot net framework so I'm thinking of removing old installs (2 and 3 with service packs) to make room for the newer version. Will things stop working or is the dot net framework backwards compatible?

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migrated from Jan 5 '12 at 10:29

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Also take a look at Piriform CCleaner. It's a freeware very very very efficient to junk useless files (iis log files, recycled items, application's caches, etc.) – Steve B Jan 5 '12 at 10:33
If you use Web platform installer, you can also empty C:\Users\you\AppData\Local\Microsoft\Web Platform Installer\installers to spare some space – Steve B Jan 5 '12 at 10:34
Short answer (prior to keyboardP's fix for it below) is Yes things will stop working :) – HaydnWVN Jan 5 '12 at 10:49
up vote 5 down vote accepted

If you remove the previous frameworks, then you'll have to edit the application config files of applications that target pre-4.0 frameworks to get them to work.

<supportedruntime version="v4.0.x"></supportedruntime>

There's an explanation here and here. If you run quite a few .NET programs, I'm sure there are other things on your machine that you can uninstall that has lower priority.

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updating all app.config file of all application, already installed or installed in the future will be so painful, you'll regret not to have bought a $80 new hard drive. – Steve B Jan 5 '12 at 10:31
Agreed. I fail to see the only resort to obtaining more disk space being to uninstall previous .NET frameworks. – keyboardP Jan 5 '12 at 10:32
I concur - repairing and compacting a PST or clearing the temp folder (+older temporary internet files) would be a much easier way to clear some space! – HaydnWVN Jan 5 '12 at 10:47
Working for a huge company that using XP on 30 GB c drive I have to make the best of what I got - that's engineering :) – ihatetoregister Jan 5 '12 at 11:21
You have my sympathy :D Ultimately, it is possible to do that but you'll have to manually fix any program you come across that was built against the previous frameworks. Might be easier to remove 1.1/2.0 if you think most programs at 3.0+ and see if that provides enough space. – keyboardP Jan 5 '12 at 11:23

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