diff --git a/common/unarj.cpp b/common/unarj.cpp
index 64203d5c663..58f326c1ac7 100644
--- a/common/unarj.cpp
+++ b/common/unarj.cpp
@@ -550,7 +550,7 @@ void ArjFile::decode() {
 	r = 0;
 
 	while (count < _origsize) {
-		if ((c = decode_c()) <= UCHAR_MAX) {
+		if ((c = decode_c()) <= ARJ_UCHAR_MAX) {
 			_text[r] = (byte) c;
 			count++;
 			if (++r >= DDICSIZ) {
@@ -558,7 +558,7 @@ void ArjFile::decode() {
 				_outstream->write(_text, DDICSIZ);
 			}
 		} else {
-			j = c - (UCHAR_MAX + 1 - THRESHOLD);
+			j = c - (ARJ_UCHAR_MAX + 1 - THRESHOLD);
 			count += j;
 			i = decode_p();
 			if ((i = r - i - 1) < 0)
@@ -591,7 +591,7 @@ void ArjFile::decode() {
 #define GETBITS(c,l) {if(_getlen<l)BFIL c=(uint16)_getbuf>>(CODE_BIT-l);BPUL(l)}
 
 int16 ArjFile::decode_ptr() {
-	int16 c;
+	int16 c = 0;
 	int16 width;
 	int16 plus;
 	int16 pwr;
@@ -612,7 +612,7 @@ int16 ArjFile::decode_ptr() {
 }
 
 int16 ArjFile::decode_len() {
-	int16 c;
+	int16 c = 0;
 	int16 width;
 	int16 plus;
 	int16 pwr;
diff --git a/common/unarj.h b/common/unarj.h
index 28424f70bd4..289ab52ad04 100644
--- a/common/unarj.h
+++ b/common/unarj.h
@@ -44,13 +44,13 @@ namespace Common {
 
 #define CODE_BIT    16
 #define CHAR_BIT  8
-#define UCHAR_MAX 255
+#define ARJ_UCHAR_MAX 255		// UCHAR_MAX is defined in limits.h in MSVC
 #define THRESHOLD	3
 #define DDICSIZ	  26624
 #define MAXDICBIT   16
 #define MATCHBIT	 8
 #define MAXMATCH   256
-#define NC		  (UCHAR_MAX + MAXMATCH + 2 - THRESHOLD)
+#define NC		  (ARJ_UCHAR_MAX + MAXMATCH + 2 - THRESHOLD)
 #define NP		  (MAXDICBIT + 1)
 #define CBIT		 9
 #define NT		  (CODE_BIT + 3)