diff --git a/hplip-hpfax-importerror-print.patch b/hplip-hpfax-importerror-print.patch
new file mode 100644
index 0000000..8d487c4
--- /dev/null
+++ b/hplip-hpfax-importerror-print.patch
@@ -0,0 +1,19 @@
+commit cdf5cb36e5d5a86f6a690c5861666cdc2da70593
+Author: Tomas Korbar <tkorbar@redhat.com>
+Date:   Wed Sep 19 15:33:03 2018 +0200
+
+    Fix TypeError in hpfax
+
+diff --git a/fax/backend/hpfax.py b/fax/backend/hpfax.py
+index 9560e84..bc0912a 100755
+--- a/fax/backend/hpfax.py
++++ b/fax/backend/hpfax.py
+@@ -89,7 +89,7 @@ try:
+     from base import utils
+     from prnt import cups
+ except ImportError as e:
+-    bug("Error importing HPLIP modules: %s\n" % (pid, e))
++    bug("Error importing HPLIP modules: %s\n" % (e))
+     sys.exit(1)
+ 
+ def handle_sigpipe():
diff --git a/hplip.spec b/hplip.spec
index 794b2b4..3966512 100644
--- a/hplip.spec
+++ b/hplip.spec
@@ -7,7 +7,7 @@
 Summary: HP Linux Imaging and Printing Project
 Name: hplip
 Version: 3.18.6
-Release: 6%{?dist}
+Release: 7%{?dist}
 License: GPLv2+ and MIT and BSD and IJG and Public Domain and GPLv2+ with exceptions and ISC
 
 Url: https://developers.hp.com/hp-linux-imaging-and-printing
@@ -50,6 +50,7 @@ Patch31: hplip-use-binary-str.patch
 # m278-m281 doesn't work correctly again
 Patch32: hplip-colorlaserjet-mfp-m278-m281.patch
 Patch33: hplip-error-print.patch
+Patch34: hplip-hpfax-importerror-print.patch
 
 Requires: %{name}-libs%{?_isa} = %{version}-%{release}
 Requires: python3-pillow
@@ -256,6 +257,9 @@ rm prnt/hpcups/ErnieFilter.{cpp,h} prnt/hpijs/ernieplatform.h
 # TypeError: 'Error' object does not support indexing (bug #1564770)
 %patch33 -p1 -b .error-print-fix
 
+# TypeError: not all arguments converted during string formatting (bug #1566938)
+%patch34 -p1 -b .hpfax-import-error-print
+
 sed -i.duplex-constraints \
     -e 's,\(UIConstraints.* \*Duplex\),//\1,' \
     prnt/drv/hpcups.drv.in
@@ -541,6 +545,9 @@ rm -f %{buildroot}%{_sysconfdir}/xdg/autostart/hplip-systray.desktop
 %config(noreplace) %{_sysconfdir}/sane.d/dll.d/hpaio
 
 %changelog
+* Tue Sep 25 2018 Tomas Korbar <tkorbar@redhat.com> - 3.18.6-7
+- 1566938 - Fix TypeError when printing ImportError message in hpfax
+
 * Tue Sep 18 2018 Tomas Korbar <tkorbar@redhat.com> - 3.18.6-6
 - 1564770 - Fix TypeError when printing error object message