Short description of error
In blender when you duplicate an animation clip or add a new animation Action, that Animation is by default set to be purged when you close the blender scene.
In order to tell blender to keep the Action- the user has to toggle on a small "F" button every time he or she creates a new Action.
What makes matters even worse is that blender gives absolutely no warning message that it is going to purge your animation and the "F" button is really easy to overlook.
It has in facts caused me to lose a massive amount of work more than twice.
I posted about this at the forum to see if others have had the same problem and it turns out yes- they had lost data too:
This is absolutely unacceptable design. No other software deletes your data when you close it- WITHOUT A WARNING. When you save your scene, you expect the application to save everything that is on the screen. The only case where you want the software to delete datablocks is when specifically told to by the user- with a confirmation message. Since blender does the opposite of that- people coming from other software will almost always lose their animation before learning that little detail about blender. Even after knowing about it, I keep making the same mistake. When there is time pressure it is easy to overlook this and lose ALL of your animation work.
This is really bad design here. I am not against data blocks. I am against how they are managed at the moment - the fact that the software is not transparent enough and it wipes your data without warning! It is doing something really bad without any warning and it is badly communicated too.
So my proposal is to Blender's GUI design team and to Blender's main developer theme. Starting from low hanging fruits to higher hanging fruits:
- When the Action has no users (F button is toggled off) Add some visual clue that is clearly warning the user that the clip will be purged by blender. You can use color coding - like marking the text in red. And also append to the name of the clip a string - like "<name of clip> (wipe data)"
- When closing blender- Warn the user about Actions that are going to be wiped.
- Blender defaults-when the user creates a new clip, set it's "F" button to be switched on by default. That way the user tells blender to erase the action when erasure is needed, rather than telling blender to KEEP the action. That way the decision to delete the action is their hands.
- Blender needs a better way of managing data blocks. -There should be an operator to wipe data blocks that have no users- a command the the user calls. Clearing data blocks without users should be done only when demanded by the users, NOT automatically by the software.
- Editing data blocks should not be done in the list where they are selected. It should be done in the outliner instead. A dedicated editor to find, select, copy, paste, and delete datablocks.
- In case you decide to keep the insane "F" button design - A BIG warning message prompt before closing the scene - listing all data blocks that the software is about to purge.
That is all, I hope you consider fixing this.
Exact steps for others to reproduce the error
Based on a (as simple as possible) attached .blend file with minimum amount of steps