diff --git a/src-tauri/src/database/dao/providers.rs b/src-tauri/src/database/dao/providers.rs
index 4f4259e95..bf0a44361 100644
--- a/src-tauri/src/database/dao/providers.rs
+++ b/src-tauri/src/database/dao/providers.rs
@@ -375,6 +375,19 @@ impl Database {
             params![app_type, category],
         )
         .map_err(|e| AppError::Database(e.to_string()))?;
+        // OMO ↔ OMO Slim mutually exclusive: deactivate the opposite category
+        let opposite = match category {
+            "omo" => Some("omo-slim"),
+            "omo-slim" => Some("omo"),
+            _ => None,
+        };
+        if let Some(opp) = opposite {
+            tx.execute(
+                "UPDATE providers SET is_current = 0 WHERE app_type = ?1 AND category = ?2",
+                params![app_type, opp],
+            )
+            .map_err(|e| AppError::Database(e.to_string()))?;
+        }
         let updated = tx
             .execute(
                 "UPDATE providers SET is_current = 1 WHERE id = ?1 AND app_type = ?2 AND category = ?3",
diff --git a/src-tauri/src/services/provider/mod.rs b/src-tauri/src/services/provider/mod.rs
index fdd9daa51..bde2dd925 100644
--- a/src-tauri/src/services/provider/mod.rs
+++ b/src-tauri/src/services/provider/mod.rs
@@ -513,6 +513,8 @@ impl ProviderService {
                 state,
                 &crate::services::omo::STANDARD,
             )?;
+            // OMO ↔ OMO Slim mutually exclusive: remove Slim config
+            let _ = crate::services::OmoService::delete_config_file(&crate::services::omo::SLIM);
             return Ok(SwitchResult::default());
         }
 
@@ -522,6 +524,10 @@ impl ProviderService {
                 .db
                 .set_omo_provider_current(app_type.as_str(), id, "omo-slim")?;
             crate::services::OmoService::write_config_to_file(state, &crate::services::omo::SLIM)?;
+            // OMO ↔ OMO Slim mutually exclusive: remove Standard config
+            let _ = crate::services::OmoService::delete_config_file(
+                &crate::services::omo::STANDARD,
+            );
             return Ok(SwitchResult::default());
         }