diff --git a/copyparty/__main__.py b/copyparty/__main__.py
index 88f3fdec..87203f87 100644
--- a/copyparty/__main__.py
+++ b/copyparty/__main__.py
@@ -553,6 +553,7 @@ def run_argparse(argv, formatter):
     ap2.add_argument("--no-mutagen", action="store_true", help="use FFprobe for tags instead; will catch more tags")
     ap2.add_argument("--no-mtag-ff", action="store_true", help="never use FFprobe as tag reader; is probably safer")
     ap2.add_argument("--mtag-mt", metavar="CORES", type=int, default=cores, help="num cpu cores to use for tag scanning")
+    ap2.add_argument("--mtag-v", action="store_true", help="verbose tag scanning; print errors from mtp subprocesses and such")
     ap2.add_argument("-mtm", metavar="M=t,t,t", type=u, action="append", help="add/replace metadata mapping")
     ap2.add_argument("-mte", metavar="M,M,M", type=u, help="tags to index/display (comma-sep.)",
         default="circle,album,.tn,artist,title,.bpm,key,.dur,.q,.vq,.aq,vc,ac,res,.fps,ahash,vhash")
diff --git a/copyparty/mtag.py b/copyparty/mtag.py
index 454fd43f..60a7584f 100644
--- a/copyparty/mtag.py
+++ b/copyparty/mtag.py
@@ -493,7 +493,7 @@ class MTag(object):
 
                 cmd = [fsenc(x) for x in cmd]
                 rc, v, err = runcmd(cmd, **args)
-                retchk(rc, cmd, err, self.log, 5)
+                retchk(rc, cmd, err, self.log, 5, self.args.mtag_v)
                 v = v.strip()
                 if not v:
                     continue
diff --git a/copyparty/util.py b/copyparty/util.py
index e41bce83..a01fdfdb 100644
--- a/copyparty/util.py
+++ b/copyparty/util.py
@@ -1423,11 +1423,11 @@ def mchkcmd(argv, timeout=10):
         raise sp.CalledProcessError(rv, (argv[0], b"...", argv[-1]))
 
 
-def retchk(rc, cmd, serr, logger=None, color=None):
+def retchk(rc, cmd, serr, logger=None, color=None, verbose=False):
     if rc < 0:
         rc = 128 - rc
 
-    if rc < 126:
+    if not rc or rc < 126 and not verbose:
         return
 
     s = None
@@ -1440,6 +1440,8 @@ def retchk(rc, cmd, serr, logger=None, color=None):
         s = "invalid program"
     elif rc == 127:
         s = "program not found"
+    elif verbose:
+        s = "unknown"
     else:
         s = "invalid retcode"