diff --git a/src/instance.rs b/src/instance.rs
index 321db95..d70a465 100644
--- a/src/instance.rs
+++ b/src/instance.rs
@@ -5,7 +5,7 @@ use std::{
 };
 
 use globset::{Glob, GlobSet, GlobSetBuilder};
-use log::warn;
+use log::{error, warn};
 
 use crate::{
     file_conflict_solver::ConflictSolver,
@@ -20,7 +20,7 @@ pub fn insert_mod_to_instance(
     from_mod: &ModConfig,
     files: &[ModFile],
     priority: isize,
-) {
+) -> bool {
     let mut solver = ConflictSolver::new();
 
     let mut installed_files: Vec<(ModFile, &InstalledMod)> = Vec::new();
@@ -40,7 +40,14 @@ pub fn insert_mod_to_instance(
     let new_mod = InstalledMod::new(from_mod.id(), priority);
     for file in files {
         if let Some(conflict) = solver.add_file(file, &new_mod) {
-            // TODO: Return conflict
+            error!(
+                "File conflict detected at: {} between {} and {}",
+                conflict.rhs_file.dst().to_string_lossy(),
+                conflict.lhs_mod.mod_id(),
+                conflict.rhs_mod.mod_id()
+            );
+
+            return false;
         }
     }
 
@@ -64,6 +71,8 @@ pub fn insert_mod_to_instance(
     for (_, installed_mod) in map {
         instance.update_or_create_mod(&installed_mod);
     }
+
+    true
 }
 
 pub fn files_to_install_mod(
diff --git a/src/main.rs b/src/main.rs
index 1d24936..3145186 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -39,7 +39,9 @@ fn command_add(root_config: &RootConfig, instance_id: &str, mod_id: &str) -> any
 
     let files = files_to_install_mod(root_config, &instance, mod_to_install)?;
 
-    insert_mod_to_instance(&mut instance, mod_to_install, &files, 0);
+    if !insert_mod_to_instance(&mut instance, mod_to_install, &files, 0) {
+        return Err(anyhow!("File conflict"));
+    }
 
     instance.save_to_file()?;