diff --git a/src/core/out.c b/src/core/out.c
index 4d220a64358..4b5ea1ccc94 100644
--- a/src/core/out.c
+++ b/src/core/out.c
@@ -311,8 +311,6 @@ out_common(const char *file, int line, const char *func, int level,
 	const char *sep = "";
 	char errstr[UTIL_MAX_ERR_MSG] = "";
 
-	unsigned long olast_error = 0;
-
 	if (file) {
 		char *f = strrchr(file, OS_DIR_SEPARATOR);
 		if (f)
@@ -335,15 +333,7 @@ out_common(const char *file, int line, const char *func, int level,
 		if (*fmt == '!') {
 			sep = ": ";
 			fmt++;
-			if (*fmt == '!') {
-				fmt++;
-				/* it will abort on non Windows OS */
-				util_strwinerror(olast_error, errstr,
-					UTIL_MAX_ERR_MSG);
-			} else {
-				util_strerror(oerrno, errstr, UTIL_MAX_ERR_MSG);
-			}
-
+			util_strerror(oerrno, errstr, UTIL_MAX_ERR_MSG);
 		}
 		ret = vsnprintf(&buf[cc], MAXPRINT - cc, fmt, ap);
 		if (ret < 0) {
@@ -365,11 +355,12 @@ out_common(const char *file, int line, const char *func, int level,
  * out_error -- common error output code, all error messages go through here
  */
 static void
-out_error(const char *file, int line, const char *func,
+out_error(int use_errno, const char *file, int line, const char *func,
 		const char *suffix, const char *fmt, va_list ap)
 {
-	int oerrno = errno;
-	unsigned long olast_error = 0;
+	int oerrno = 0;
+	if (use_errno)
+		oerrno = errno;
 	unsigned cc = 0;
 	unsigned print_msg = 1;
 	int ret;
@@ -392,17 +383,9 @@ out_error(const char *file, int line, const char *func,
 			fmt++;
 		}
 
-		if (*fmt == '!') {
+		if (use_errno) {
 			sep = ": ";
-			fmt++;
-			if (*fmt == '!') {
-				fmt++;
-				/* it will abort on non Windows OS */
-				util_strwinerror(olast_error, errstr,
-					UTIL_MAX_ERR_MSG);
-			} else {
-				util_strerror(oerrno, errstr, UTIL_MAX_ERR_MSG);
-			}
+			util_strerror(oerrno, errstr, UTIL_MAX_ERR_MSG);
 		}
 
 		ret = vsnprintf(&errormsg[cc], MAXPRINT, fmt, ap);
@@ -449,7 +432,8 @@ out_error(const char *file, int line, const char *func,
 #endif
 
 end:
-	errno = oerrno;
+	if (use_errno)
+		errno = oerrno;
 }
 
 /*
@@ -528,13 +512,13 @@ out_fatal(const char *file, int line, const char *func,
  * out_err -- output an error message
  */
 void
-out_err(const char *file, int line, const char *func,
+out_err(int use_errno, const char *file, int line, const char *func,
 		const char *fmt, ...)
 {
 	va_list ap;
 	va_start(ap, fmt);
 
-	out_error(file, line, func, "\n", fmt, ap);
+	out_error(use_errno, file, line, func, "\n", fmt, ap);
 
 	va_end(ap);
 }
diff --git a/src/core/out.h b/src/core/out.h
index 22d9b520a2f..c0914ac2c1c 100644
--- a/src/core/out.h
+++ b/src/core/out.h
@@ -184,18 +184,18 @@ out_fatal_abort(const char *file, int line, const char *func,
 		ASSERTne_rt(lhs, rhs);\
 	} while (0)
 
-#define ERR(...)\
-	out_err(__FILE__, __LINE__, __func__, __VA_ARGS__)
+#define ERR(use_errno, ...)\
+	out_err(use_errno, __FILE__, __LINE__, __func__, __VA_ARGS__)
 
 #define ERR_W_ERRNO(f, ...)\
 	do {\
-		ERR("*!" f, ##__VA_ARGS__);\
+		ERR(1, "*" f, ##__VA_ARGS__);\
 		CORE_LOG_ERROR_WITH_ERRNO(f, ##__VA_ARGS__);\
 	} while (0)
 
 #define ERR_WO_ERRNO(f, ...)\
 	do {\
-		ERR("*" f, ##__VA_ARGS__);\
+		ERR(0, "*" f, ##__VA_ARGS__);\
 		CORE_LOG_ERROR(f, ##__VA_ARGS__);\
 	} while (0)
 
@@ -209,8 +209,8 @@ void out_log_va(const char *file, int line, const char *func, int level,
 		const char *fmt, va_list ap);
 void out_log(const char *file, int line, const char *func, int level,
 	const char *fmt, ...) FORMAT_PRINTF(5, 6);
-void out_err(const char *file, int line, const char *func,
-	const char *fmt, ...) FORMAT_PRINTF(4, 5);
+void out_err(int use_errno, const char *file, int line, const char *func,
+	const char *fmt, ...) FORMAT_PRINTF(5, 6);
 void NORETURN out_fatal(const char *file, int line, const char *func,
 	const char *fmt, ...) FORMAT_PRINTF(4, 5);
 const char *out_get_errormsg(void);
diff --git a/src/core/util.h b/src/core/util.h
index 0224aaa774d..003a48da1b9 100644
--- a/src/core/util.h
+++ b/src/core/util.h
@@ -1,5 +1,5 @@
 /* SPDX-License-Identifier: BSD-3-Clause */
-/* Copyright 2014-2023, Intel Corporation */
+/* Copyright 2014-2024, Intel Corporation */
 /*
  * Copyright (c) 2016-2020, Microsoft Corporation. All rights reserved.
  *
@@ -101,7 +101,6 @@ int util_snprintf(char *str, size_t size,
 
 #define UTIL_MAX_ERR_MSG 128
 void util_strerror(int errnum, char *buff, size_t bufflen);
-void util_strwinerror(unsigned long err, char *buff, size_t bufflen);
 
 void util_set_alloc_funcs(
 		void *(*malloc_func)(size_t size),
diff --git a/src/core/util_posix.c b/src/core/util_posix.c
index b3bd924f34a..2d7558e48c8 100644
--- a/src/core/util_posix.c
+++ b/src/core/util_posix.c
@@ -23,17 +23,6 @@ util_strerror(int errnum, char *buff, size_t bufflen)
 	strerror_r(errnum, buff, bufflen);
 }
 
-/*
- * util_strwinerror -- should never be called on posix OS - abort()
- */
-void
-util_strwinerror(unsigned long err, char *buff, size_t bufflen)
-{
-	/* suppress unused-parameter errors */
-	SUPPRESS_UNUSED(err, buff, bufflen);
-	abort();
-}
-
 /*
  * util_part_realpath -- get canonicalized absolute pathname
  *
diff --git a/src/test/out_err/out_err.c b/src/test/out_err/out_err.c
index a3b6552487c..fca1809a9b9 100644
--- a/src/test/out_err/out_err.c
+++ b/src/test/out_err/out_err.c
@@ -41,13 +41,13 @@ main(int argc, char *argv[])
 
 	errno = EBADF;
 	strerror_r(errno, buff, UT_MAX_ERR_MSG);
-	out_err(__FILE__, 100, __func__,
+	out_err(0, __FILE__, 100, __func__,
 		"ERR1: %s:%d", buff, 1234);
 	UT_OUT("%s", out_get_errormsg());
 
 	errno = EBADF;
 	strerror_r(errno, buff, UT_MAX_ERR_MSG);
-	out_err(NULL, 0, NULL,
+	out_err(0, NULL, 0, NULL,
 		"ERR2: %s:%d", buff, 1234);
 	UT_OUT("%s", out_get_errormsg());
 
diff --git a/src/tools/pmempool/output.c b/src/tools/pmempool/output.c
index 63df4f5244b..19b2527464a 100644
--- a/src/tools/pmempool/output.c
+++ b/src/tools/pmempool/output.c
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: BSD-3-Clause
-/* Copyright 2014-2023, Intel Corporation */
+/* Copyright 2014-2024, Intel Corporation */
 
 /*
  * output.c -- definitions of output printing related functions
@@ -774,7 +774,7 @@ out_get_incompat_features_str(uint32_t incompat)
 		/* print the value and the left square bracket */
 		ret = util_snprintf(str_buff, STR_MAX, "0x%x [", incompat);
 		if (ret < 0) {
-			ERR("snprintf for incompat features: %d", ret);
+			ERR(0, "snprintf for incompat features: %d", ret);
 			return "<error>";
 		}
 
diff --git a/src/tools/pmempool/output.h b/src/tools/pmempool/output.h
index 80922f2ec0a..0b86ac1f759 100644
--- a/src/tools/pmempool/output.h
+++ b/src/tools/pmempool/output.h
@@ -1,5 +1,5 @@
 /* SPDX-License-Identifier: BSD-3-Clause */
-/* Copyright 2014-2023, Intel Corporation */
+/* Copyright 2014-2024, Intel Corporation */
 
 /*
  * output.h -- declarations of output printing related functions
@@ -14,8 +14,8 @@ void out_set_stream(FILE *stream);
 void out_set_prefix(const char *prefix);
 void out_set_col_width(unsigned col_width);
 void outv_err(const char *fmt, ...) FORMAT_PRINTF(1, 2);
-void out_err(const char *file, int line, const char *func,
-		const char *fmt, ...) FORMAT_PRINTF(4, 5);
+void out_err(int use_errno, const char *file, int line, const char *func,
+		const char *fmt, ...) FORMAT_PRINTF(5, 6);
 void outv_err_vargs(const char *fmt, va_list ap);
 void outv_indent(int vlevel, int i);
 void outv(int vlevel, const char *fmt, ...) FORMAT_PRINTF(2, 3);