diff --git a/test/functional/api/cas/cli_messages.py b/test/functional/api/cas/cli_messages.py
index 566b551..09a8d8f 100644
--- a/test/functional/api/cas/cli_messages.py
+++ b/test/functional/api/cas/cli_messages.py
@@ -7,7 +7,6 @@ import re
 from core.test_run import TestRun
 from test_utils.output import Output
 
-
 load_inactive_core_missing = [
     r"WARNING: Can not resolve path to core \d+ from cache \d+\. By-id path will be shown for that "
     r"core\.",
@@ -18,8 +17,7 @@ start_cache_with_existing_metadata = [
     r"Error inserting cache \d+",
     r"Old metadata found on device\.",
     r"Please load cache metadata using --load option or use --force to",
-    r" discard on-disk metadata and start fresh cache instance\.",
-    r"Error occurred, please see syslog \(/var/log/messages\) for details\."
+    r" discard on-disk metadata and start fresh cache instance\."
 ]
 
 error_inserting_cache = [
@@ -42,6 +40,12 @@ stop_cache_incomplete = [
     r"Cache is in incomplete state - at least one core is inactive"
 ]
 
+stop_cache_errors = [
+    r"Error while removing cache \d+",
+    r"Error while writing to cache device",
+    r"Error occurred, please see syslog \(/var/log/messages\) for details"
+]
+
 get_stats_ioclass_id_not_configured = [
     r"IO class \d+ is not configured\."
 ]
@@ -60,6 +64,11 @@ add_cached_core = [
     r"Core device \'/dev/\S+\' is already cached\."
 ]
 
+already_cached_core = [
+    r"Error while adding core device to cache instance \d+",
+    r"Device already added as a core"
+]
+
 remove_mounted_core = [
     r"Can\'t remove core \d+ from cache \d+\. Device /dev/cas\d+-\d+ is mounted\!"
 ]
diff --git a/test/functional/tests/fault_injection/test_fault_injection_with_mounted_core.py b/test/functional/tests/fault_injection/test_fault_injection_with_mounted_core.py
index cff6194..df89e06 100644
--- a/test/functional/tests/fault_injection/test_fault_injection_with_mounted_core.py
+++ b/test/functional/tests/fault_injection/test_fault_injection_with_mounted_core.py
@@ -163,7 +163,7 @@ def test_add_cached_core(cache_mode):
     with TestRun.step("Try adding the same core device to the same cache for the second time."):
         output = TestRun.executor.run_expect_fail(
             cli.add_core_cmd(cache_id=str(cache1.cache_id), core_dev=str(core_part.path)))
-        cli_messages.check_stderr_msg(output, cli_messages.add_cached_core)
+        cli_messages.check_stderr_msg(output, cli_messages.already_cached_core)
 
     with TestRun.step("Stop caches."):
         casadm.stop_all_caches()
diff --git a/test/functional/tests/lazy_writes/recovery/test_recovery_unplug.py b/test/functional/tests/lazy_writes/recovery/test_recovery_unplug.py
index d5df969..f028cfe 100644
--- a/test/functional/tests/lazy_writes/recovery/test_recovery_unplug.py
+++ b/test/functional/tests/lazy_writes/recovery/test_recovery_unplug.py
@@ -4,12 +4,15 @@
 #
 
 import os
+
 import pytest
-from api.cas import casadm
+
+from api.cas import casadm, cli_messages
 from api.cas.cache_config import CacheMode, CacheModeTrait, CacheLineSize
 from core.test_run import TestRun
 from storage_devices.disk import DiskTypeSet, DiskType, DiskTypeLowerThan
 from test_tools.disk_utils import Filesystem
+from test_utils.output import CmdException
 from test_utils.size import Size, Unit
 from tests.lazy_writes.recovery.recovery_tests_methods import create_test_files, copy_file, \
     compare_files
@@ -148,7 +151,11 @@ def test_recovery_unplug_cache_raw(cache_mode, cls):
                             f"{cache.get_dirty_blocks().get_value(Unit.Blocks4096)}")
 
     with TestRun.step("Stop cache."):
-        cache.stop()
+        try:
+            cache.stop(no_data_flush=True)
+            TestRun.LOGGER.warning("Expected stopping cache with errors.")
+        except CmdException as e:
+            cli_messages.check_stderr_msg(e.output, cli_messages.stop_cache_errors)
 
     with TestRun.step("Plug missing cache device."):
         cache_disk.plug()