I assume you mean the colors change when you view your video on YouTube? If so, perhaps this is something you need to take up with YT. Inevitably, uploaded videos are "changed" by YT in order to accommodate different viewing circumstances and internet speeds.
If the problem is NOT that YT changes the colors but the problem is occurring when you actually create the Export, please read this post and come back with ALL the detail requested there, about your computer and the exact version and variant of MEP you are using.
Not all web browsers are colour correct when viewing from the web. Stills photographers complain about this all the time. It's possibly your web browser. This has been proven on a few photography forums for stills viewing.
Having said that, when you upload to any hosting site, the file is going to be re-rendered again so care should be taken over your export settings. It has been a consensus on the forums that I have visited broaching this subject for stills in the past, that Firefox is possibly the most accurate web browser for this. Whether this opinion is still current or not I couldn't say, but I am having no problems in that regard using Firefox at present for stills or video viewing.
As Jeff has pointed out it could be your export settings but I have found choice of web browser to be important as well.
It has something to do with the export settings because my animations look all wonky even when I export them to video. I’ve tried fixing the rendering but it’s the same. I’m using the free trial version so maybe that’s part of it? And I’m using a windows 10. This is really stressing me out because of how frustrating it is, I just want high quality animations. When I export my videos the once pastel and colorful picture turns way too bright. I really need to fix this!
Then I suggest you give us your complete machine spec please and the program settings you have chosen in the programs project manager. Have for instance have you activated 'dithering for output'? What is the resolution of your project? What are the settings for your exports?
The more information we have, the more likely it is someone may be able to offer an answer. I think some plugins can't be activated in the trial version but personally I never used the trial version so can't honestly answer that question.
Hey guys chill out. The background you need to know: I am a mom who has no idea about any of these things and I have a child who is a great artists and is using the program to do amazing 2D animations. My child doesn’t know anything about edition programs and this is the first time owning a laptop. My child has been using whatever was pre set in Vegas pro settings. The animation is done with the program fire alpaca and it looks great, color is great. But when exporting to Sony Vegas colors change. Please explain with a lot of patience what are the tech specifications you need, how do we find out and how to incorporate them in this profile. Also if you have suggestions for beginners wanting to use if this program for animation that would be great.
By not indicating which program you have in your first post, you wasted the time of those who posted.
When you post on the Vegas forum, provide the requested information or else they will ask you for it. If you have Sony Vegas 14 or more recent or you say that you have, there is no such program and you will be sent to a link explaining just that.