diff --git a/moo/lib/comp.c b/moo/lib/comp.c
index 819880e..8c1c47d 100644
--- a/moo/lib/comp.c
+++ b/moo/lib/comp.c
@@ -7728,9 +7728,9 @@ static int __compile_class_definition (moo_t* moo, int extend)
 			 *  this extra module name, i'm free from GC headache */
 			if (moo_importmod (moo, moo->c->cls.self_oop, moo->c->cls.modname.ptr, moo->c->cls.modname.len) <= -1)
 			{
-				moo_copyoocstr (moo->errmsg.tmpbuf.ooch, MOO_COUNTOF(moo->errmsg.tmpbuf.ooch), moo->errmsg.buf);
+				const moo_ooch_t* oldmsg = moo_backuperrmsg(moo);
 				set_syntax_errbfmt (moo, MOO_SYNERR_MODIMPFAIL, &moo->c->cls.modname_loc, &moo->c->cls.modname,
-						"unable to import %.*js - %js", moo->c->cls.modname.len, moo->c->cls.modname.ptr, moo->errmsg.tmpbuf.ooch);
+						"unable to import %.*js - %js", moo->c->cls.modname.len, moo->c->cls.modname.ptr, oldmsg);
 				return -1;
 			}
 		}
diff --git a/moo/lib/err.c b/moo/lib/err.c
index aefc4de..5299a1b 100644
--- a/moo/lib/err.c
+++ b/moo/lib/err.c
@@ -306,6 +306,12 @@ const moo_ooch_t* moo_geterrmsg (moo_t* moo)
 	return moo->errmsg.buf;
 }
 
+const moo_ooch_t* moo_backuperrmsg (moo_t* moo)
+{
+	moo_copyoocstr (moo->errmsg.tmpbuf.ooch, MOO_COUNTOF(moo->errmsg.tmpbuf.ooch), moo->errmsg.buf);
+	return moo->errmsg.tmpbuf.ooch;
+}
+
 void moo_seterrwithsyserr (moo_t* moo, int syserr)
 {
 	if (moo->vmprim.syserrstrb)
diff --git a/moo/lib/exec.c b/moo/lib/exec.c
index 542cd71..2123b8c 100644
--- a/moo/lib/exec.c
+++ b/moo/lib/exec.c
@@ -1140,8 +1140,8 @@ static int add_to_sem_io (moo_t* moo, moo_oop_semaphore_t sem, moo_ooi_t io_hand
 		tmp = moo_reallocmem (moo, moo->sem_io_map, MOO_SIZEOF(*tmp) * new_capa);
 		if (!tmp) 
 		{
-			moo_copyoocstr (moo->errmsg.tmpbuf.ooch, MOO_COUNTOF(moo->errmsg.tmpbuf.ooch), moo->errmsg.buf);
-			moo_seterrbfmt (moo, moo->errnum, "handle %zd out of supported range - %js", moo->errmsg.tmpbuf.ooch);
+			const moo_ooch_t* oldmsg = moo_backuperrmsg(moo);
+			moo_seterrbfmt (moo, moo->errnum, "handle %zd out of supported range - %js", oldmsg);
 			return -1;
 		}
 
@@ -2555,8 +2555,8 @@ static moo_pfrc_t __system_add_io_semaphore (moo_t* moo, moo_ooi_t nargs, moo_se
 
 	if (add_to_sem_io(moo, sem, MOO_OOP_TO_SMOOI(fd), io_type) <= -1) 
 	{
-		moo_copyoocstr (moo->errmsg.tmpbuf.ooch, MOO_COUNTOF(moo->errmsg.tmpbuf.ooch), moo->errmsg.buf);
-		moo_seterrbfmt (moo, moo->errnum, "cannot add the handle %zd to the multiplexer - %js", MOO_OOP_TO_SMOOI(fd), moo->errmsg.tmpbuf.ooch);
+		const moo_ooch_t* oldmsg = moo_backuperrmsg(moo);
+		moo_seterrbfmt (moo, moo->errnum, "cannot add the handle %zd to the multiplexer - %js", MOO_OOP_TO_SMOOI(fd), oldmsg);
 		return MOO_PF_FAILURE;
 	}
 
@@ -2615,8 +2615,8 @@ static moo_pfrc_t pf_system_remove_semaphore (moo_t* moo, moo_ooi_t nargs)
 
 		if (delete_from_sem_io (moo, sem) <= -1)
 		{
-			moo_copyoocstr (moo->errmsg.tmpbuf.ooch, MOO_COUNTOF(moo->errmsg.tmpbuf.ooch), moo->errmsg.buf);
-			moo_seterrbfmt (moo, moo->errnum, "cannot delete the handle %zd from the multiplexer - %js", MOO_OOP_TO_SMOOI(sem->io_handle), moo->errmsg.tmpbuf.ooch);
+			const moo_ooch_t* oldmsg = moo_backuperrmsg(moo);
+			moo_seterrbfmt (moo, moo->errnum, "cannot delete the handle %zd from the multiplexer - %js", MOO_OOP_TO_SMOOI(sem->io_handle), oldmsg);
 			return MOO_PF_FAILURE;
 		}
 
diff --git a/moo/lib/moo.h b/moo/lib/moo.h
index 100b020..9457d50 100644
--- a/moo/lib/moo.h
+++ b/moo/lib/moo.h
@@ -1670,11 +1670,15 @@ MOO_EXPORT void moo_seterrwithsyserr (
 	int    syserr
 );
 
+MOO_EXPORT const moo_ooch_t* moo_geterrstr (
+	moo_t* moo
+);
+
 MOO_EXPORT const moo_ooch_t* moo_geterrmsg (
 	moo_t* moo
 );
 
-MOO_EXPORT const moo_ooch_t* moo_geterrstr (
+MOO_EXPORT const moo_ooch_t* moo_backuperrmsg (
 	moo_t* moo
 );