diff --git a/mwrpy/exceptions.py b/mwrpy/exceptions.py
index 8b6ed7e..5eaccc1 100644
--- a/mwrpy/exceptions.py
+++ b/mwrpy/exceptions.py
@@ -4,3 +4,7 @@ class MissingInputData(Exception):
 
 class InvalidFileError(Exception):
     pass
+
+
+class MissingCoefficientsError(Exception):
+    pass
diff --git a/mwrpy/level1/quality_control.py b/mwrpy/level1/quality_control.py
index cbc3c12..5b6270f 100644
--- a/mwrpy/level1/quality_control.py
+++ b/mwrpy/level1/quality_control.py
@@ -1,6 +1,7 @@
 """Quality control for level1 data."""
 
 import datetime
+import logging
 
 import netCDF4 as nc
 import numpy as np
@@ -8,6 +9,7 @@
 import suncalc
 from numpy import ma
 
+from mwrpy.exceptions import MissingCoefficientsError
 from mwrpy.level1.rpg_bin import RpgBin
 from mwrpy.level2.get_ret_coeff import get_mvr_coeff
 from mwrpy.level2.write_lev2_nc import retrieval_input
@@ -66,8 +68,14 @@ def apply_qc(
     if params["flag_status"][3] == 1 or "air_pressure" not in data:
         data["quality_flag_status"] = setbit(data["quality_flag_status"], 3)
     else:
-        ind = spectral_consistency(data, site, coeff_files)
-        data["quality_flag"][ind] = setbit(data["quality_flag"][ind], 3)
+        try:
+            ind = spectral_consistency(data, site, coeff_files)
+            data["quality_flag"][ind] = setbit(data["quality_flag"][ind], 3)
+        except MissingCoefficientsError as e:
+            logging.error(
+                f"Error in spectral consistency check: {e}. Proceeding without flagging."
+            )
+            data["quality_flag_status"] = setbit(data["quality_flag_status"], 3)
 
     # Bit 5: Receiver sanity
     if params["flag_status"][4] == 1:
@@ -307,6 +315,9 @@ def spectral_consistency(
     else:
         c_list = get_coeff_list(site, "tbx", coeff_files)
 
+        if not c_list:
+            raise MissingCoefficientsError("No coefficients found")
+
         for ifreq, _ in enumerate(data["frequency"]):
             with nc.Dataset(c_list[ifreq]) as cfile:
                 _, freq_ind, coeff_ind = np.intersect1d(