diff --git a/bitbake/lib/bb/fetch2/npm.py b/bitbake/lib/bb/fetch2/npm.py
index 699ae72e05..c3e02e47f0 100644
--- a/bitbake/lib/bb/fetch2/npm.py
+++ b/bitbake/lib/bb/fetch2/npm.py
@@ -258,17 +258,23 @@ class Npm(FetchMethod):
 
         shwrf = d.getVar('NPM_SHRINKWRAP', True)
         logger.debug(2, "NPM shrinkwrap file is %s" % shwrf)
-        try:
-            with open(shwrf) as datafile:
-                shrinkobj = json.load(datafile)
-        except:
+        if shwrf:
+            try:
+                with open(shwrf) as datafile:
+                    shrinkobj = json.load(datafile)
+            except Exception as e:
+                raise FetchError('Error loading NPM_SHRINKWRAP file "%s" for %s: %s' % (shwrf, ud.pkgname, str(e)))
+        elif not ud.ignore_checksums:
             logger.warning('Missing shrinkwrap file in NPM_SHRINKWRAP for %s, this will lead to unreliable builds!' % ud.pkgname)
         lckdf = d.getVar('NPM_LOCKDOWN', True)
         logger.debug(2, "NPM lockdown file is %s" % lckdf)
-        try:
-            with open(lckdf) as datafile:
-                lockdown = json.load(datafile)
-        except:
+        if lckdf:
+            try:
+                with open(lckdf) as datafile:
+                    lockdown = json.load(datafile)
+            except Exception as e:
+                raise FetchError('Error loading NPM_LOCKDOWN file "%s" for %s: %s' % (lckdf, ud.pkgname, str(e)))
+        elif not ud.ignore_checksums:
             logger.warning('Missing lockdown file in NPM_LOCKDOWN for %s, this will lead to unreproducible builds!' % ud.pkgname)
 
         if ('name' not in shrinkobj):