Version:           1.4.0 (using KDE 4.5.5) 
OS:                Linux

In early June 2011 I noticed that most pictures taken in 2011 have lost the tags that I had set including i) old tag categories and ii) newly created tag categories. Also, some newly created tag categories have disappeared, i.e. are no longer available in the tag hierarchy.

The concerned picture set was worked on over many sessions during several months. In other words, a single crash with loss of unsaved data does not explain the issue I am reporting.

I have appx 20k images in my archive, of which appx 2k are taken in 2011. I have an extensive tag hierarchy including responses to "who", "what" and "where". I use digikam successfully since 2006, and have never before encountered this sort of meta data loss. 

Please advise on what elements would be of help; logs? sqlite db? 

Reproducible: Couldn't Reproduce

Steps to Reproduce:
(re)Created some tags that were lost. (re) Tagged some of the pictures that lost their tags, with both old and new tags. 

Actual Results:  
Closing DK, and restarting DK does not show any anomalies. The tagged pictures still have their tags, old and new.

Expected Results:  
Digikam should not lose (meta)data.

Hard to reproduce, for sure, but (meta) data loss is critical as countless hours of work tagging and categorizing my pictures has simply vanished. I will restore a backup, but my confidence in the otherwise excellent and trustworthy sw digikam has suffered.