diff --git a/proto/backend.proto b/proto/backend.proto
index bcbad1ba2..5ec8ab440 100644
--- a/proto/backend.proto
+++ b/proto/backend.proto
@@ -131,6 +131,7 @@ message BackendError {
         SyncError sync_error = 7;
         // user interrupted operation
         Empty interrupted = 8;
+        string json_error = 9;
     }
 }
 
diff --git a/rslib/src/backend/mod.rs b/rslib/src/backend/mod.rs
index 4178373db..9dbeea795 100644
--- a/rslib/src/backend/mod.rs
+++ b/rslib/src/backend/mod.rs
@@ -76,6 +76,7 @@ fn anki_error_to_proto_error(err: AnkiError, i18n: &I18n) -> pb::BackendError {
         AnkiError::CollectionNotOpen => V::InvalidInput(pb::Empty {}),
         AnkiError::CollectionAlreadyOpen => V::InvalidInput(pb::Empty {}),
         AnkiError::SchemaChange => V::InvalidInput(pb::Empty {}),
+        AnkiError::JSONError { info } => V::JsonError(info),
     };
 
     pb::BackendError {
diff --git a/rslib/src/err.rs b/rslib/src/err.rs
index 0f57259be..96c9b3b83 100644
--- a/rslib/src/err.rs
+++ b/rslib/src/err.rs
@@ -31,6 +31,9 @@ pub enum AnkiError {
     #[fail(display = "Sync error: {:?}, {}", kind, info)]
     SyncError { info: String, kind: SyncErrorKind },
 
+    #[fail(display = "JSON encode/decode error: {}", info)]
+    JSONError { info: String },
+
     #[fail(display = "The user interrupted the operation.")]
     Interrupted,
 
@@ -223,7 +226,9 @@ impl From<zip::result::ZipError> for AnkiError {
 
 impl From<serde_json::Error> for AnkiError {
     fn from(err: serde_json::Error) -> Self {
-        AnkiError::sync_misc(err.to_string())
+        AnkiError::JSONError {
+            info: err.to_string(),
+        }
     }
 }