Collaborative Computational Project No. 4
Software for Macromolecular X-Ray Crystallography

Reporting a problem to CCP4

If you are reporting problems with using CCP4 software

CCP4 is updated on a rolling basis during which many bugs are fixed and new features added. Please ensure that you are on the latest version.

If you have found a bug with the current version. please send as much information as you can to help CCP4 staff identify and fix the problem - typically we will need to know the following:

Please send this information to us at

Problems with older versions of the suite are listed at the problems pages.

If you wish to post to CCP4bb

The CCP4 Bulletin Board is a very active community resource for discussions of relevance to macromolecular crystallographers. Questions of scientific content are best addressed here. Note that you will first need to be correctly subscribed to the list; details can be found on the CCP4bb page.

To post to CCP4bb, register as above then send an e-mail to