Old attachments (from 2018 and earlier) use a deprecated encryption method and must be updated in the Web Vault. More recently, a small number of users were affected by a bug that corrupted some file attachments in vault items that were edited during the summer months of 2025.
If you are referring to something different, please provide additional detail by posting in the following thread (if it seems relevant to your situation), or by starting a new thread of your own:
To avoid diverting the topic of this feature request (which would be in violation of forum rules), please do not respond in this thread.