diff --git a/CHANGELOG.md b/CHANGELOG.md
index 48b321a1..6676c69b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,7 +10,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ### Fixes
 - Arch
+    - not stopping the upgrade process if a transaction error happens
     - wrong dialog titles
+    
 
 ## [0.9.0] - 2020-04-15
 ### Features
diff --git a/bauh/commons/system.py b/bauh/commons/system.py
index d2e67220..20eb0aff 100644
--- a/bauh/commons/system.py
+++ b/bauh/commons/system.py
@@ -65,7 +65,7 @@ class SimpleProcess:
 
     def __init__(self, cmd: List[str], cwd: str = '.', expected_code: int = None,
                  global_interpreter: bool = USE_GLOBAL_INTERPRETER, lang: str = DEFAULT_LANG, root_password: str = None,
-                 extra_paths: Set[str] = None):
+                 extra_paths: Set[str] = None, error_phrases: Set[str] = None):
         pwdin, final_cmd = None, []
 
         if root_password is not None:
@@ -76,6 +76,7 @@ class SimpleProcess:
 
         self.instance = self._new(final_cmd, cwd, global_interpreter, lang, stdin=pwdin, extra_paths=extra_paths)
         self.expected_code = expected_code
+        self.error_phrases = error_phrases
 
     def _new(self, cmd: List[str], cwd: str, global_interpreter: bool, lang: str, stdin = None, extra_paths: Set[str] = None) -> subprocess.Popen:
 
@@ -175,8 +176,18 @@ class ProcessHandler:
                         
                     self._notify_watcher(line)
 
+        proc.instance.wait()
         output.seek(0)
-        return proc.instance.returncode == proc.expected_code, output.read()
+
+        success = proc.instance.returncode == proc.expected_code,
+        string_output = output.read()
+
+        if proc.error_phrases:
+            for phrase in proc.error_phrases:
+                if phrase in string_output:
+                    success = False
+                    break
+        return success, string_output
 
 
 def run_cmd(cmd: str, expected_code: int = 0, ignore_return_code: bool = False, print_error: bool = True,
diff --git a/bauh/gems/arch/controller.py b/bauh/gems/arch/controller.py
index 3a8b744f..ef4ed038 100644
--- a/bauh/gems/arch/controller.py
+++ b/bauh/gems/arch/controller.py
@@ -741,7 +741,7 @@ class ArchManager(SoftwareManager):
                     disk.save_several(repo_pkgs_names, repo_map=repo_map, overwrite=True, maintainer=None)
 
                 else:
-                    self.logger.error("'pacman' returned an unexpected response after upgrading the repository packages")
+                    self.logger.error("'pacman' returned an unexpected response or error phrase after upgrading the repository packages")
                     return False
             except:
                 watcher.change_substatus('')
diff --git a/bauh/gems/arch/pacman.py b/bauh/gems/arch/pacman.py
index df85427e..9a8c2d3b 100644
--- a/bauh/gems/arch/pacman.py
+++ b/bauh/gems/arch/pacman.py
@@ -141,7 +141,10 @@ def install_as_process(pkgpaths: Iterable[str], root_password: str, file: bool,
     else:
         cmd = ['pacman', '-S', *pkgpaths, '--noconfirm']  # pkgpath = pkgname
 
-    return SimpleProcess(cmd=cmd, root_password=root_password, cwd=pkgdir)
+    return SimpleProcess(cmd=cmd,
+                         root_password=root_password,
+                         cwd=pkgdir,
+                         error_phrases={"error: failed to prepare transaction"})
 
 
 def list_desktop_entries(pkgnames: Set[str]) -> List[str]:
@@ -692,7 +695,9 @@ def list_installed_names() -> Set[str]:
 
 
 def upgrade_several(pkgnames: Iterable[str], root_password: str) -> SimpleProcess:
-    return SimpleProcess(cmd=['pacman', '-S', *pkgnames, '--noconfirm'], root_password=root_password)
+    return SimpleProcess(cmd=['pacman', '-S', *pkgnames, '--noconfirm'],
+                         root_password=root_password,
+                         error_phrases={'error: failed to prepare transaction'})
 
 
 def remove_several(pkgnames: Iterable[str], root_password: str) -> SystemProcess: