What to do so that the lessons learned remain in the organization and are documented and do not go only in the knowledge of people?

From my point of view, if you have the feeling that the people that leave the company, take the knowledge with them, is because your company is not working or didn't implement a properly Knowledge Management.

A correct Knowledge Management implementation at the organization level will ensure the correct knowledge transfer between team members.

Thank you for bringing up the addition of pictures to Lessons Learned files. That has been an excellent way for us to illustrate context of many of the Lessons Learned that we have documented.

In my experience, the lessons learnt are not captured or if captured not well documented. Most of the times the lessons learnt are captured in a presentation form or a document form. At Closure of a project, the Project manager presents the lessons learnt and stores it in a central location. The files are lying there without proper tagging of data and can't be easily searched.

A software solution should be used that allows you to tag the project's lesson learnt under relevant headings (type, domain, region, etc.) which makes the information easily searchable based on different search criterias and useful in the future.

Lessons learned need to be store in a general zone of the corporate network otherwise they get lost has project come to a close.

They need to be structure so to have easy search, recognize keywords.

@Eduin - I believe the key to retaining lessons learned is not really in the documenting or storing thereof but rather in the implementation. Documenting and storing lessons learned is only the first step in retention. Retaining lessons learned is nothing more that an archiving exercise if they are not implemented and they might just as well stay inside the heads of those who learned then in the first place. By implementing them immediately in the relevant processes you are guaranteed to retain them.

I am not a big fan of the 'make a note, we will fix it next time' approach. Not that there is anything wrong with the recording of an issue but I do not have enough space at my disposal for all the documented lessons learned that were never implemented. Implementation is a form of documentation in itself if done correctly.

Lessons learned may be classified - within each project or program - in a breakdown structure, i.e. Technical; Resourcing; Financial; Logistics; etc. which could make the archive and look up processes leaner or more efficient.