diff --git a/launcher/app/assets/js/processbuilder.js b/launcher/app/assets/js/processbuilder.js
index 9cf5cd0..948400a 100644
--- a/launcher/app/assets/js/processbuilder.js
+++ b/launcher/app/assets/js/processbuilder.js
@@ -754,13 +754,14 @@ class ProcessBuilder {
                             }
                         })
 
-                        // Extract the file.
+                        // Extract the file (synchrone, voir bloc 1.19+).
                         if(!shouldExclude){
-                            fs.writeFile(path.join(tempNativePath, fileName), zipEntries[i].getData(), (err) => {
-                                if(err){
-                                    logger.error('Error while extracting native library:', err)
-                                }
-                            })
+                            try {
+                                fs.writeFileSync(path.join(tempNativePath, fileName), zipEntries[i].getData())
+                                fs.writeFileSync(path.join(tempNativePath, 'java', fileName), zipEntries[i].getData())
+                            } catch(err) {
+                                logger.error('Error while extracting native library:', err)
+                            }
                         }
 
                     }
@@ -806,14 +807,15 @@ class ProcessBuilder {
                         const extractName = fileName.includes('/') ? fileName.substring(fileName.lastIndexOf('/')) : fileName
 
                         // Extract the file (racine pour compat + sous-dossier java/ exigé par MC récent).
+                        // Synchrone : le jeu démarre aussitôt après, l'async faisait rater les grosses .so.
                         if(!shouldExclude){
                             const data = zipEntries[i].getData()
                             for(const dest of [path.join(tempNativePath, extractName), path.join(tempNativePath, 'java', extractName)]){
-                                fs.writeFile(dest, data, (err) => {
-                                    if(err){
-                                        logger.error('Error while extracting native library:', err)
-                                    }
-                                })
+                                try {
+                                    fs.writeFileSync(dest, data)
+                                } catch(err) {
+                                    logger.error('Error while extracting native library:', err)
+                                }
                             }
                         }