diff --git a/problemtools/verifyproblem.py b/problemtools/verifyproblem.py
index ccd09ef8..f2e91304 100644
--- a/problemtools/verifyproblem.py
+++ b/problemtools/verifyproblem.py
@@ -1166,9 +1166,12 @@ def collect_flags(group: TestCaseGroup, flags: set[str]) -> None:
 
             def modified_input_validates(applicable, modifier):
                 for testcase in self.problem.testdata.get_all_testcases():
-                    with open(testcase.infile) as infile:
-                        infile_data = infile.read()
-                    if not applicable(infile_data):
+                    try:
+                        with open(testcase.infile) as infile:
+                            infile_data = infile.read()
+                        if not applicable(infile_data):
+                            continue
+                    except UnicodeDecodeError:
                         continue
 
                     with open(file_name, 'wb') as f: