# UnsupportedOperationException causes snapshots to fail **URL:** \ **Category:** Elasticsearch\ **Created:** [September 18, 2020, 9:48pm UTC](https://discuss.elastic.co/t/unsupportedoperationexception-causes-snapshots-to-fail/249181 "2020-09-18T21:48:37Z")\ **Posts on this page:** 1\ **Showing post:** 2
**Author:** ![Armin\_Braun](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/armin_braun/32/20092_2.png) [@Armin\_Braun](https://discuss.elastic.co/u/Armin_Braun)\ **Post date:** [September 21, 2020, 12:44pm UTC](https://discuss.elastic.co/t/unsupportedoperationexception-causes-snapshots-to-fail/249181/2 "2020-09-21T12:44:03Z")
Hi @OliviaTrewin I think there is a backwards compatibility issue with the data structures the source-only snapshot keeps on disk between snapshots here and an outdated version of this data is not getting cleaned up. I'm trying to reproduce this currently and will open an issue for it once I have. I think you should be able to work around this problem by deleting the `_snapshot` directories in your shard folders like e.g. `/mnt/istore/elasticsearch/data/nodes/0/indices/vDAnJnfiTkWOZ7nOv4GMDw/126/_snapshot` so that the on-disk data structures are re-created with a supported Lucene version. EDIT: I opened [https://github.com/elastic/elasticsearch/issues/62700](https://github.com/elastic/elasticsearch/issues/62700) to track a fix for this. --- _[View the full topic](https://discuss.elastic.co/t/unsupportedoperationexception-causes-snapshots-to-fail/249181)._