Salesforce has strict limits on the number of fields that you can customize. Most people are familiar with these field limits, for example, a Developer Edition org can have up to 500 custom fields, while Unlimited and Performance allows 800 custom fields in total. However, there is a much smaller limit for the Field History Tracking feature.
Regardless of your Salesforce edition, history tracking cannot be turned on for more than 20 fields total, counting all fields of all objects in your org.
If you can’t turn off history tracking for other fields, try one of the following alternative solutions.
For the very technically inclined, there is a cool Stack Overflow suggestion that explains how to create a Custom Object and an Apex trigger for tracking history, sidestepping the Salesforce feature completely. You can find example code there. This is a complicated solution for advanced users.
Try to contact Salesforce support and ask for the limit to be increased. We have heard of people getting this limit increased to a maximum of 50 fields, but no more. This may not be available for all users. Your mileage may vary.
Blue Canvas can automate your deployments.
Our app automatically handles issues like this. Our unique deployment engine talks directly to Salesforce and knows how to work around errors like this one and many others. With Blue Canvas, your deployments can be quick and simple, so you deploy in seconds not hours.