diff --git a/src/Composer/Installer.php b/src/Composer/Installer.php
index ace3fa17b..570317fff 100644
--- a/src/Composer/Installer.php
+++ b/src/Composer/Installer.php
@@ -475,7 +475,7 @@ class Installer
             $this->io->writeError('<info>Installing dependencies'.($withDevReqs ? ' (including require-dev)' : '').' from lock file</info>');
 
             if (!$this->locker->isFresh()) {
-                $this->io->writeError('<warning>Warning: The lock file is not up to date with the latest changes in composer.json. You may be getting outdated dependencies. Run update to update them.</warning>');
+                $this->io->writeError('<warning>Warning: The lock file is not up to date with the latest changes in composer.json. You may be getting outdated dependencies. Run update to update them.</warning>', true, IOInterface::QUIET);
             }
 
             foreach ($lockedRepository->getPackages() as $package) {
@@ -515,7 +515,7 @@ class Installer
             $operations = $solver->solve($request, $this->ignorePlatformReqs);
             $this->eventDispatcher->dispatchInstallerEvent(InstallerEvents::POST_DEPENDENCIES_SOLVING, $this->devMode, $policy, $pool, $installedRepo, $request, $operations);
         } catch (SolverProblemsException $e) {
-            $this->io->writeError('<error>Your requirements could not be resolved to an installable set of packages.</error>');
+            $this->io->writeError('<error>Your requirements could not be resolved to an installable set of packages.</error>', true, IOInterface::QUIET);
             $this->io->writeError($e->getMessage());
 
             return max(1, $e->getCode());