Hey, thanks for the report. This is a known issue with the Prettier extension after a recent update.
Workaround: No longer eligible as formatter for many types of files · Issue #3906 · prettier/prettier-vscode · GitHub (you need to downgrade Prettier to a version < 12.0.0)
Root cause: Cursor doesn’t support ESM extensions yet, which newer versions of Prettier require. The team is tracking this, but the downgrade workaround should help for now.
Similar report with a solution: Prettier broke after updating Cursor to 2.39.41