It is common for people to dislike change. When curriculum implementation is taking place there may be resistance to the the new ideas and innovations presented. Thomas Harvey has provided a list of common reasons people may resist change.
Lack of ownership. Change must be an internal movement to have success. If the ideas are coming from an outside push success is much less likely to happen. Few people enjoy taking orders from external powers.
Lack of benefit. If teachers do not see any advantages to the new program for themselves or their students, they may not accept it. The strong points of a new curriculum must be explained.
More work. Few teachers want more to do. Change often brings additional responsibilities, at least, initially. Wise implementation entails removing current responsibilities in order not to overburden teachers with too much work.
Lack of support. This is closely related to the previous point. If leadership does not support the change, the workers will not either. The example and support of administration is key to success of any change happening in an organization.
Insecurity. The risk of failure is always present when new ideas are tried. This can make some people really hesitant to try new ideas. A supportive atmosphere where failure is okay is needed for dealing with this. If people look bad using a new curriculum they will not use it for long.
Incongruence with Norm. The philosophy and beliefs laid down in the innovation must be consisted with the beliefs of the people who will use it. If there is a conflict in beliefs there will be a potential rejection of the innovation. This is especially true over controversial topics like sexual orientation, abortion, or creation.
Chaos. Change often brings disorder. If the amount of chaos and disorder is perceived as too high people may resist. People want change that brings order and not disorder.
Complete/wholesale change. A change that calls for a complete revamp of a current system is too much for most people to handle. An incremental approach is much more acceptable when dealing with bringing curriculum change. Many schools will role out a new curriculum a grade at a time rather than all at once. This helps the students and gives the teachers time to prepare.
There are many other reasons besides these that my be the root cause of resistance to curriculum change in a school. These reasons serve to provide a basic introduction into causes for resistance.