diff --git a/.gitignore b/.gitignore
index 3d09413dc..36a5009dc 100644
--- a/.gitignore
+++ b/.gitignore
@@ -82,4 +82,5 @@ doc/*.nwb
 B95.zip
 grouped_ephys
 uv.lock
-.venv
\ No newline at end of file
+.venv
+.python-version
\ No newline at end of file
diff --git a/neo/rawio/axonrawio.py b/neo/rawio/axonrawio.py
index ef6df08f6..7351a5008 100644
--- a/neo/rawio/axonrawio.py
+++ b/neo/rawio/axonrawio.py
@@ -680,12 +680,18 @@ def _parse_abf_v1(f, header_description):
     YY = 1900
     MM = 1
     DD = 1
-    hh = int(header["lFileStartTime"] / 3600.0)
-    mm = int((header["lFileStartTime"] - hh * 3600) / 60)
-    ss = header["lFileStartTime"] - hh * 3600 - mm * 60
-    ms = int(np.mod(ss, 1) * 1e6)
-    ss = int(ss)
-    header["rec_datetime"] = datetime.datetime(YY, MM, DD, hh, mm, ss, ms)
+    seconds_per_day = 24 * 3600
+    # A "no date" file writes the 0xFFFFFFFF sentinel, which reads as a negative time; fall back to
+    # rec_datetime=None instead of crashing on the resulting out-of-range time-of-day.
+    if not (0 <= header["lFileStartTime"] < seconds_per_day):
+        header["rec_datetime"] = None
+    else:
+        hh = int(header["lFileStartTime"] / 3600.0)
+        mm = int((header["lFileStartTime"] - hh * 3600) / 60)
+        ss = header["lFileStartTime"] - hh * 3600 - mm * 60
+        ms = int(np.mod(ss, 1) * 1e6)
+        ss = int(ss)
+        header["rec_datetime"] = datetime.datetime(YY, MM, DD, hh, mm, ss, ms)
 
     return header
 
@@ -1029,15 +1035,22 @@ def _parse_abf_v2(f, header_description):
         header["EpochInfo"].append(EpochInfo)
 
     # date and time
-    YY = int(header["uFileStartDate"] / 10000)
-    MM = int((header["uFileStartDate"] - YY * 10000) / 100)
-    DD = int(header["uFileStartDate"] - YY * 10000 - MM * 100)
-    hh = int(header["uFileStartTimeMS"] / 1000.0 / 3600.0)
-    mm = int((header["uFileStartTimeMS"] / 1000.0 - hh * 3600) / 60)
-    ss = header["uFileStartTimeMS"] / 1000.0 - hh * 3600 - mm * 60
-    ms = int(np.mod(ss, 1) * 1e6)
-    ss = int(ss)
-    header["rec_datetime"] = datetime.datetime(YY, MM, DD, hh, mm, ss, ms)
+    # A "no date" sentinel (0 = unset, 0xFFFFFFFF = all bits set) has no valid date to build, so
+    # fall back to rec_datetime=None. Any other value is trusted and left to raise if genuinely out
+    # of range, so a real parsing error surfaces rather than being masked.
+    no_date_sentinels = (0, 0xFFFFFFFF)
+    if header["uFileStartDate"] in no_date_sentinels:
+        header["rec_datetime"] = None
+    else:
+        YY = int(header["uFileStartDate"] / 10000)
+        MM = int((header["uFileStartDate"] - YY * 10000) / 100)
+        DD = int(header["uFileStartDate"] - YY * 10000 - MM * 100)
+        hh = int(header["uFileStartTimeMS"] / 1000.0 / 3600.0)
+        mm = int((header["uFileStartTimeMS"] / 1000.0 - hh * 3600) / 60)
+        ss = header["uFileStartTimeMS"] / 1000.0 - hh * 3600 - mm * 60
+        ms = int(np.mod(ss, 1) * 1e6)
+        ss = int(ss)
+        header["rec_datetime"] = datetime.datetime(YY, MM, DD, hh, mm, ss, ms)
 
     return header
 
diff --git a/neo/test/rawiotest/test_axonrawio.py b/neo/test/rawiotest/test_axonrawio.py
index a9986b692..50c5ce389 100644
--- a/neo/test/rawiotest/test_axonrawio.py
+++ b/neo/test/rawiotest/test_axonrawio.py
@@ -1,6 +1,6 @@
 import unittest
 
-from neo.rawio.axonrawio import AxonRawIO
+from neo.rawio.axonrawio import AxonRawIO, parse_axon_soup
 
 from neo.test.rawiotest.common_rawio_test import BaseTestRawIO
 
@@ -28,6 +28,18 @@ def test_read_raw_protocol(self):
 
         reader.read_raw_protocol()
 
+    def test_invalid_date_falls_back_to_none(self):
+        # Some ABF files store an out-of-range / "no date" sentinel (e.g. 0xFFFFFFFF)
+        # in the acquisition date header fields. The date is non-essential annotation,
+        # so parsing must fall back to rec_datetime=None rather than raising and
+        # blocking access to the signal.
+        for fixture in [
+            "axon/intracellular_data/files_with_errors/invalid_date_abf1.abf",  # ABF v1
+            "axon/intracellular_data/files_with_errors/invalid_date_abf2.abf",  # ABF v2
+        ]:
+            header = parse_axon_soup(self.get_local_path(fixture))
+            self.assertIsNone(header["rec_datetime"])
+
     def test_non_unique_channel_ids_fall_back_to_sequential_ids(self):
         # Some version < 2.0 ABF files (e.g. re-saved exports) corrupt nADCSamplingSeq so every
         # entry is identical, which yields non-unique channel ids. AxonRawIO detects this, warns,