diff --git a/pyproject.toml b/pyproject.toml
index a8c9a0d..c3905ee 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -34,8 +34,7 @@ pandas = "^2.2.3"
 omit = [".*", "*/site-packages/*", "Snakefile"]
 
 [tool.black]
-line-length = 87
-target-version = ['py311']
+line-length = 88
 
 [build-system]
 requires = ["poetry-core"]
diff --git a/snakemake_executor_plugin_slurm/__init__.py b/snakemake_executor_plugin_slurm/__init__.py
index 2abb5ba..b534f90 100644
--- a/snakemake_executor_plugin_slurm/__init__.py
+++ b/snakemake_executor_plugin_slurm/__init__.py
@@ -45,6 +45,7 @@
 )
 from .efficiency_report import create_efficiency_report
 from .submit_string import get_submit_command
+from .validation import validate_or_get_slurm_job_id, validate_slurm_extra
 from .partitions import read_partition_file, get_best_partition
 from .validation import (
     validate_slurm_extra,
@@ -539,8 +540,10 @@ def run_job(self, job: JobExecutorInterface):
         # To extract the job id we split by semicolon and take the first
         # element (this also works if no cluster name was provided)
         slurm_jobid = out.strip().split(";")[0]
-        if not slurm_jobid:
-            raise WorkflowError("Failed to retrieve SLURM job ID from sbatch output.")
+        # this slurm_jobid might be wrong: some cluster admin give convoluted
+        # sbatch outputs. So we need to validate it properly (and replace it
+        # if necessary).
+        slurm_jobid = validate_or_get_slurm_job_id(slurm_jobid, out)
         slurm_logfile = slurm_logfile.with_name(
             slurm_logfile.name.replace("%j", slurm_jobid)
         )
diff --git a/snakemake_executor_plugin_slurm/validation.py b/snakemake_executor_plugin_slurm/validation.py
index 497ad6a..4931a29 100644
--- a/snakemake_executor_plugin_slurm/validation.py
+++ b/snakemake_executor_plugin_slurm/validation.py
@@ -8,6 +8,64 @@
 from .job_status_query import get_min_job_age, is_query_tool_available
 
 
+def validate_or_get_slurm_job_id(job_id, output):
+    """
+    Validate that the SLURM job ID is a positive integer.
+
+    Args:
+        job_id (str): The SLURM job ID to validate.
+        output (str): The full sbatch output to parse if job_id is invalid.
+
+    Raises:
+        WorkflowError: If the job ID is not a positive integer or we cannot
+                       determine a valid job ID from the given input string.
+    """
+    # this regex just matches a positive integer
+    # strict validation would require to check for a JOBID with either
+    # the SLURM database or control daemon. This is too much overhead.
+    if re.match(r"^\d+$", job_id):
+        return job_id
+    else:
+        # Try matching a positive integer, raise an error if more than one match or
+        # no match found. Match standalone integers, excluding those followed by %,
+        # letters, or digits (units/percentages/floats). Allows format: "1234" or
+        # "1234; clustername" (SLURM multi-cluster format).
+
+        # If the first attempt to validate the job fails, try parsing the sbatch output
+        # a bit more sophisticatedly.
+        # The regex below matches standalone positive integers with a word boundary
+        # before the number. The number must NOT be:
+        # - Part of a decimal number (neither before nor after the dot)
+        # - Followed by a percent sign with optional space (23% or 23 %)
+        # - Followed by units/counts with optional space:
+        #   * Memory units: k, K, m, M, g, G, kiB, KiB, miB, MiB, giB, GiB
+        #   * Resource counts: files, cores, hours, cpus/CPUs (case-insensitive)
+        #   * minutes are excluded, because of the match to 'm' for Megabytes
+        #   Units must be followed by whitespace, hyphen, period, or end of string
+        # Use negative lookbehind to exclude digits after a dot, and negative lookahead
+        # to exclude digits before a dot or followed by units/percent
+        matches = re.findall(
+            r"(?<![.\d])\d+(?![.\d]|\s*%|\s*(?:[kKmMgG](?:iB)?|files|cores|"
+            r"hours|[cC][pP][uU][sS]?)(?:\s|[-.]|$))",
+            output,
+        )
+        if len(matches) == 1:
+            return matches[0]
+        elif len(matches) > 1:
+            raise WorkflowError(
+                f"Multiple possible SLURM job IDs found in: {output}. "
+                "Was looking for exactly one positive integer."
+            )
+        elif not matches:
+            raise WorkflowError(
+                f"No valid SLURM job ID found in: {output}. "
+                "Was looking for exactly one positive integer. "
+                "We tried our best to parse the sbatch output, but it appears "
+                "too convoluted. Please run 'sbatch' manually and report the output "
+                "to us. If the output is garbled, inform your cluster administrators."
+            )
+
+
 def get_forbidden_slurm_options():
     """
     Return a dictionary of forbidden SLURM options that the executor manages.
diff --git a/tests/tests.py b/tests/tests.py
index 955bc8f..fb6cbaf 100644
--- a/tests/tests.py
+++ b/tests/tests.py
@@ -13,8 +13,10 @@
 )
 from snakemake_executor_plugin_slurm.utils import set_gres_string
 from snakemake_executor_plugin_slurm.submit_string import get_submit_command
-
-from snakemake_executor_plugin_slurm.validation import validate_slurm_extra
+from snakemake_executor_plugin_slurm.validation import (
+    validate_slurm_extra,
+    validate_or_get_slurm_job_id,
+)
 from snakemake_interface_common.exceptions import WorkflowError
 import pandas as pd
 
@@ -863,3 +865,193 @@ def test_multiple_forbidden_options(self, mock_job):
         # Should raise error for job-name (first one encountered)
         with pytest.raises(WorkflowError, match=r"job-name.*not allowed"):
             validate_slurm_extra(job)
+
+
+class TestSlurmJobIdValidation:
+    """Test cases for the validate_or_get_slurm_job_id function."""
+
+    def test_parsable_format_simple(self):
+        """Test parsable format with just job ID."""
+        output = "12345"
+        result = validate_or_get_slurm_job_id("12345", output)
+        assert result == "12345"
+
+    def test_parsable_format_with_cluster(self):
+        """Test parsable format with cluster name (jobid;clustername)."""
+        output = "54321;mycluster"
+        result = validate_or_get_slurm_job_id("54321", output)
+        assert result == "54321"
+
+    def test_convoluted_output_with_percentages(self):
+        """Test extraction from output containing percentages."""
+        output = """Lorem ipsum dolor sit amet, consectetur adipiscing elit.
+Maecenas quis risus porttitor: 25%
+pretium enim volutpat: 23.3%
+Submitted batch job 88888
+some other text"""
+        result = validate_or_get_slurm_job_id("88888", output)
+        assert result == "88888"
+
+    def test_convoluted_output_with_units(self):
+        """Test extraction from output containing memory/size units."""
+        output = """System information:
+Memory available: 256 GiB
+CPU usage: 12 cores
+Storage: 500 G
+Job ID: 77777
+Files processed: 1500 files"""
+        result = validate_or_get_slurm_job_id("77777", output)
+        assert result == "77777"
+
+    def test_convoluted_output_mixed(self):
+        """Test extraction with percentages, decimals, and units mixed."""
+        output = """Cluster status report
+Queue utilization: 75.5%
+Memory allocated: 128 KiB per node
+Disk usage: 23.3 % of quota
+Allocated space: 50 G
+Processing 3000 files
+Your job 123456 has been submitted
+"""
+        result = validate_or_get_slurm_job_id("123456", output)
+        assert result == "123456"
+
+    def test_job_id_at_beginning(self):
+        """Test extraction when job ID appears at the start."""
+        output = """999888 submitted successfully
+Memory: 64 GiB
+Nodes: 4"""
+        result = validate_or_get_slurm_job_id("999888", output)
+        assert result == "999888"
+
+    def test_job_id_in_middle(self):
+        """Test extraction when job ID is in the middle of output."""
+        output = """Configuration loaded: 100%
+Job 444555 queued
+Estimated wait time: 5.5 minutes"""
+        result = validate_or_get_slurm_job_id("444555", output)
+        assert result == "444555"
+
+    def test_output_with_lowercase_units(self):
+        """Test that lowercase units are properly excluded."""
+        output = """Memory: 32 m
+Storage: 100 k files
+Job: 333222"""
+        result = validate_or_get_slurm_job_id("333222", output)
+        assert result == "333222"
+
+    def test_output_with_cores_and_cpus(self):
+        """Test that numbers followed by 'cores' or 'cpus' are excluded."""
+        output = """System resources:
+Allocated: 16 cores
+Available CPUs: 32
+Using 8 cpus
+Active cpu: 1
+Job ID: 555666"""
+        result = validate_or_get_slurm_job_id("555666", output)
+        assert result == "555666"
+
+    def test_output_with_mixed_case_units(self):
+        """Test mixed case memory units (MiB, GiB, etc.)."""
+        output = """Allocated: 512 MiB
+Reserved: 2 GiB
+Cache: 128 KiB
+Job ID is 111222"""
+        result = validate_or_get_slurm_job_id("111222", output)
+        assert result == "111222"
+
+    def test_decimal_numbers_excluded(self):
+        """Test that decimal numbers are not matched as job IDs."""
+        output = """Performance: 23.3 MB/s
+Efficiency: 99.9%
+Job: 666777
+Load: 1.5"""
+        result = validate_or_get_slurm_job_id("666777", output)
+        assert result == "666777"
+
+    def test_percentage_with_space(self):
+        """Test percentages with space before % sign."""
+        output = """Completion: 45 %
+Progress: 78.5 %
+Job ID: 555444"""
+        result = validate_or_get_slurm_job_id("555444", output)
+        assert result == "555444"
+
+    def test_units_with_hyphen(self):
+        """Test units followed by hyphen."""
+        output = """Memory: 256M-512M range
+Job: 888999"""
+        result = validate_or_get_slurm_job_id("888999", output)
+        assert result == "888999"
+
+    def test_units_with_period(self):
+        """Test units followed by period."""
+        output = """Allocated 128G. Starting job 777888."""
+        result = validate_or_get_slurm_job_id("777888", output)
+        assert result == "777888"
+
+    def test_multiple_job_ids_error(self):
+        """Test that multiple possible job IDs raise an error."""
+        output = """Previous job: 11111
+New job: 22222
+Both are active"""
+        with pytest.raises(
+            WorkflowError, match=r"Multiple possible SLURM job IDs found"
+        ):
+            validate_or_get_slurm_job_id("invalid", output)
+
+    def test_no_valid_job_id_error(self):
+        """Test that output with no valid job ID raises an error."""
+        output = """Error: 23.3%
+Memory: 128 GiB
+Status: 99.9% complete"""
+        with pytest.raises(WorkflowError, match=r"No valid SLURM job ID found"):
+            validate_or_get_slurm_job_id("invalid", output)
+
+    def test_complex_multiline_output(self):
+        """Test complex realistic SLURM output."""
+        output = """
+╔══════════════════════════════════════════════════════════════════════════════╗
+║                            SLURM Job Submission                               ║
+╚══════════════════════════════════════════════════════════════════════════════╝
+
+Cluster Information:
+  - Queue utilization: 67.8%
+  - Available memory: 512 GiB
+  - Free storage: 2.5 TiB (1500 files pending)
+
+Job Configuration:
+  - Requested memory: 64 GiB
+  - Requested time: 48.5 hours
+  - Cores: 16
+
+Submitting job 202411170001 to cluster...
+
+Status:
+  - Queue position: 23
+  - Estimated start: 15.3 minutes
+"""
+        result = validate_or_get_slurm_job_id("202411170001", output)
+        print(result)
+        assert result == "202411170001"
+
+    def test_invalid_job_id_then_extract_from_output(self):
+        """Test fallback extraction when initial job_id is malformed."""
+        output = "Submitted batch job 12345"
+        # Pass invalid job_id, should extract from output
+        result = validate_or_get_slurm_job_id("invalid_id", output)
+        assert result == "12345"
+
+    def test_job_id_with_trailing_content(self):
+        """Test job ID followed by various trailing content."""
+        output = "Job 123456 submitted to partition main"
+        result = validate_or_get_slurm_job_id("123456", output)
+        assert result == "123456"
+
+    def test_numbers_in_filenames_excluded(self):
+        """Test that numbers in 'files' counts are excluded."""
+        output = """Quota 250 files
+Used 100 files
+Job ID: 999000"""
+        result = validate_or_get_slurm_job_id("999000", output)
+        assert result == "999000"