Hello,

You can have both versions installed on your computer just fine - they are different applications. One thing you will find is that you cannot run a different version of Firefox if your current Firefox profile is already in use by another version of the browser. If you want to be able to run both versions at the same time, please see the article Profile Manager - Create, remove or switch Firefox profiles and use different profiles for each version of Firefox.

FireFox 37.0a1 is a pre-release alpha development version, which is updated frequently - usually everyday. Don't install it just because it is a 64-bit version, or because you have a 64-bit operating system - the 32-bit release version is more stable.

64 bit Nightly builds for Windows are only generated to test for compilation errors and do not undergo all the tests that other builds get, so the risk that something goes wrong can be quite high. Also the Nightly build are updated every day unlike the release build that receive an update every six weeks. If you aren't experienced to deal with issues then you should stay with the release build.

• http://kb.mozillazine.org/Testing_pre-release_versions

cor-el said

64 bit Nightly builds for Windows are only generated to test for compilation errors and do not undergo all the tests that other builds get, so the risk that something goes wrong can be quite high. Also the Nightly build are updated every day unlike the release build that receive an update every six weeks. If you aren't experienced to deal with issues then you should stay with the release build.

• http://kb.mozillazine.org/Testing_pre-release_versions

thank you for the information. I have run against this before and I should have known. Thank you again and I will take your advice.

cor-el said

64 bit Nightly builds for Windows are only generated to test for compilation errors and do not undergo all the tests that other builds get, so the risk that something goes wrong can be quite high. Also the Nightly build are updated every day unlike the release build that receive an update every six weeks. If you aren't experienced to deal with issues then you should stay with the release build.

• http://kb.mozillazine.org/Testing_pre-release_versions

I will not be using this FireFox until it has become a completed unit.

cor-el said

64 bit Nightly builds for Windows are only generated to test for compilation errors and do not undergo all the tests that other builds get, so the risk that something goes wrong can be quite high. Also the Nightly build are updated every day unlike the release build that receive an update every six weeks. If you aren't experienced to deal with issues then you should stay with the release build.

• http://kb.mozillazine.org/Testing_pre-release_versions

I will not be using this unit and in the future I will take your advice. I am only barely above a Novice and do not get involved with products in this step of the process.

The Nightly channel builds (along with Aurora (aka developer edition)) gets checkins almost everyday so therefore they get a update each of those days. They can be stable but one day a checkin(s) could make the next build(s) have issues like crashing or landed changes that are still a work in progress. It is basically for Testers, Devs and not for regular users in mind.

Firefox 37.0 however if it progresses well may be the earliest to get Win64 for Release in a first phase. https://wiki.mozilla.org/Firefox/win64