Mendeley Desktop EOL 2022; 2018 update lost user PDFs and annotations

Elsevier's acquisition of Mendeley produced two distinct losses for the research community:

1. A 2018 update caused users to lose PDFs and annotations curated inside the application. The update reorganized internal data structures in a way that broke prior data. Mendeley issued patches and partial recovery tools, but a fraction of users' annotated libraries was permanently lost.
2. End-of-life of Mendeley Desktop in September 2022, four years after the 2018 incident. Researchers using Mendeley Desktop as their primary reference manager were forced to migrate or accept feature regression in the cloud-based replacement.

The case demonstrates two distinct C-0020 mechanisms operating on the same platform: (a) data integrity loss through software change pushed by the platform owner; (b) discontinuation of a major research workflow tool on the platform owner's strategic timeline.

The annotations-loss incident is rarely cited as a research-data preservation event because the affected data was metadata about papers (notes, highlights, organizational tags), not the papers themselves. From the user's perspective, the value is in the curation; the loss of the curation is the loss of accumulated research labor. The architectural reading: a research workflow that depends on a single proprietary application's continued operation, with no export path that fully preserves curation state, is exposed to both the application's continued existence and to disruptive updates within its lifetime.