diff --git a/src/lib/file.cpp b/src/lib/file.cpp
index acb8e38..b5ca0c5 100644
--- a/src/lib/file.cpp
+++ b/src/lib/file.cpp
@@ -187,7 +187,7 @@ ErrorOrVoid File::insertByte(uint8_t byte){
         this->fileStream.seekg(0);
         this->write(readData);
         this->cursorPosition++;
-        delete buffer;
+        delete[] buffer;
     }catch(std::exception& e){
         failure = true;
     }
@@ -209,7 +209,7 @@ ErrorOrVoid File::insert(std::vector<uint8_t> data){
         this->fileStream.seekg(0);
         this->write(readData);
         this->cursorPosition += data.size();
-        delete buffer;
+        delete[] buffer;
     }catch(std::exception& e){
         failure = true;
     }
@@ -230,10 +230,9 @@ ErrorOrVoid File::insertString(tiny_utf8::string string){
 
         this->fileStream.seekg(0);
 
-        //TODO: fix hack. tinyutf8 appends "_utf-8" when readData is assigned: tiny_utf8::string((char *) buffer);
-        this->writeString(readData.substr(0, readData.find("_utf-8")));
+        this->writeString(readData);
         this->cursorPosition += string.size();
-        delete buffer;
+        delete[] buffer;
     }catch(std::exception& e){
         failure = true;
     }
@@ -257,7 +256,7 @@ ErrorOr<uint8_t> File::cutByte(){
         this->fileStream.seekg(0);
         this->write(readData);
         this->cursorPosition++;
-        delete buffer;
+        delete[] buffer;
     }catch(std::exception& e){
         failure = true;
     }