diff --git a/htdocs/core/actions_massactions.inc.php b/htdocs/core/actions_massactions.inc.php
index b86e7bd692c..dc5b02286eb 100644
--- a/htdocs/core/actions_massactions.inc.php
+++ b/htdocs/core/actions_massactions.inc.php
@@ -1030,14 +1030,18 @@ if (!$error && $massaction == "builddoc" && $permissiontoread && !GETPOST('butto
 				$input_files .= ' '.escapeshellarg($f);
 			}
 
-			$cmd = 'pdftk '.escapeshellarg($input_files).' cat output '.escapeshellarg($file);
+			$cmd = 'pdftk ' . $input_files . ' cat output '.escapeshellarg($file);
 			exec($cmd);
 
-			if (!empty($conf->global->MAIN_UMASK))
-				@chmod($file, octdec($conf->global->MAIN_UMASK));
-
-			$langs->load("exports");
-			setEventMessages($langs->trans('FileSuccessfullyBuilt', $filename.'_'.dol_print_date($now, 'dayhourlog')), null, 'mesgs');
+			// check if pdftk is installed
+			if (file_exists($file)) {
+				if (!empty($conf->global->MAIN_UMASK))
+					@chmod($file, octdec($conf->global->MAIN_UMASK));
+				$langs->load("exports");
+				setEventMessages($langs->trans('FileSuccessfullyBuilt', $filename.'_'.dol_print_date($now, 'dayhourlog')), null, 'mesgs');
+			} else {
+				setEventMessages($langs->trans('ErrorPDFTkOutputFileNotFound'), null, 'errors');
+			}
 		}
 		else
 		{
diff --git a/htdocs/langs/en_US/main.lang b/htdocs/langs/en_US/main.lang
index 31e0d5a1c8d..051dde11ff7 100644
--- a/htdocs/langs/en_US/main.lang
+++ b/htdocs/langs/en_US/main.lang
@@ -837,6 +837,7 @@ Sincerely=Sincerely
 ConfirmDeleteObject=Are you sure you want to delete this object?
 DeleteLine=Delete line
 ConfirmDeleteLine=Are you sure you want to delete this line?
+ErrorPDFTkOutputFileNotFound=Error: the file was not generated. Please check that the 'pdftk' command is installed in a directory included in the $PATH environment variable (linux/unix only) or contact your system administrator.
 NoPDFAvailableForDocGenAmongChecked=No PDF were available for the document generation among checked record
 TooManyRecordForMassAction=Too many records selected for mass action. The action is restricted to a list of %s records.
 NoRecordSelected=No record selected
@@ -1017,4 +1018,4 @@ ContactDefault_ticket=Ticket
 ContactAddedAutomatically=Contact added from contact thirdparty roles
 More=More
 ShowDetails=Show details
-CustomReports=Custom reports
\ No newline at end of file
+CustomReports=Custom reports