diff --git a/pycatfile.py b/pycatfile.py
index 5a0d289..c4397f5 100755
--- a/pycatfile.py
+++ b/pycatfile.py
@@ -3200,7 +3200,10 @@ def AppendFileHeader(fp, numfiles, fencoding, extradata=[], checksumtype="crc32"
         AppendNullByte(catfileheadercshex, formatspecs['format_delimiter'])
     catheaersize = format(int(len(fnumfilesa) - len(formatspecs['format_delimiter'])), 'x').lower()
     catheaersizestr = AppendNullByte(catheaersize, formatspecs['format_delimiter'])
-    fp.write(fnumfilesa.encode('UTF-8'))
+    try:
+        fp.write(fnumfilesa.encode('UTF-8'))
+    except OSError:
+        return False
     try:
         fp.flush()
         if(hasattr(os, "sync")):
@@ -3328,7 +3331,10 @@ def AppendFileHeaderWithContent(fp, filevalues=[], extradata=[], filecontent="",
     catfileoutstrecd = catfileoutstr.encode('UTF-8')
     nullstrecd = formatspecs['format_delimiter'].encode('UTF-8')
     catfileout = catfileoutstrecd + filecontent + nullstrecd
-    fp.write(catfileout)
+    try:
+        fp.write(catfileout)
+    except OSError:
+        return False
     try:
         fp.flush()
         if(hasattr(os, "sync")):
@@ -3630,8 +3636,11 @@ def AppendFilesWithContent(infiles, fp, dirlistfromtxt=False, filevalues=[], ext
         AppendFileHeaderWithContent(
             fp, catoutlist, extradata, fcontents.read(), [checksumtype[1], checksumtype[2]], formatspecs)
     if(numfiles > 0):
-        catfp.write(AppendNullBytes(
-            ["0", "0"], formatspecs['format_delimiter']).encode("UTF-8"))
+        try:
+            catfp.write(AppendNullBytes(
+                ["0", "0"], formatspecs['format_delimiter']).encode("UTF-8"))
+        except OSError:
+            return False
     fp.seek(0, 0)
     return fp
 
@@ -3694,8 +3703,11 @@ def AppendListsWithContent(inlist, fp, dirlistfromtxt=False, filevalues=[], extr
         AppendFileHeaderWithContent(
             fp, catoutlist, extradata, fcontents.read(), [checksumtype[1], checksumtype[2]], formatspecs)
     if(numfiles > 0):
-        fp.write(AppendNullBytes(
-            ["0", "0"], formatspecs['format_delimiter']).encode("UTF-8"))
+        try:
+            fp.write(AppendNullBytes(
+                ["0", "0"], formatspecs['format_delimiter']).encode("UTF-8"))
+        except OSError:
+            return False
     return fp
 
 
@@ -4871,8 +4883,11 @@ def PackArchiveFile(infiles, outfile, dirlistfromtxt=False, compression="auto",
             catfp, catoutlist, extradata, fcontents.read(), [checksumtype[1], checksumtype[2]], formatspecs)
         fcontents.close()
     if(numfiles > 0):
-        catfp.write(AppendNullBytes(
-            ["0", "0"], formatspecs['format_delimiter']).encode("UTF-8"))
+        try:
+            catfp.write(AppendNullBytes(
+                ["0", "0"], formatspecs['format_delimiter']).encode("UTF-8"))
+        except OSError:
+            return False
     if(outfile == "-" or outfile is None or hasattr(outfile, "read") or hasattr(outfile, "write")):
         catfp = CompressArchiveFile(
             catfp, compression, compressionlevel, formatspecs)
@@ -5149,8 +5164,11 @@ def PackArchiveFileFromTarFile(infile, outfile, compression="auto", compresswhol
             catfp, catoutlist, extradata, fcontents.read(), [checksumtype[1], checksumtype[2]], formatspecs)
         fcontents.close()
     if(numfiles > 0):
-        catfp.write(AppendNullBytes(
-            ["0", "0"], formatspecs['format_delimiter']).encode("UTF-8"))
+        try:
+            catfp.write(AppendNullBytes(
+                ["0", "0"], formatspecs['format_delimiter']).encode("UTF-8"))
+        except OSError:
+            return False
     if(outfile == "-" or outfile is None or hasattr(outfile, "read") or hasattr(outfile, "write")):
         catfp = CompressArchiveFile(
             catfp, compression, compressionlevel, formatspecs)
@@ -5416,8 +5434,11 @@ def PackArchiveFileFromZipFile(infile, outfile, compression="auto", compresswhol
             catfp, catoutlist, extradata, fcontents.read(), [checksumtype[1], checksumtype[2]], formatspecs)
         fcontents.close()
     if(numfiles > 0):
-        catfp.write(AppendNullBytes(
-            ["0", "0"], formatspecs['format_delimiter']).encode("UTF-8"))
+        try:
+            catfp.write(AppendNullBytes(
+                ["0", "0"], formatspecs['format_delimiter']).encode("UTF-8"))
+        except OSError:
+            return False
     if(outfile == "-" or outfile is None or hasattr(outfile, "read") or hasattr(outfile, "write")):
         catfp = CompressArchiveFile(
             catfp, compression, compressionlevel, formatspecs)
@@ -5713,8 +5734,11 @@ def PackArchiveFileFromRarFile(infile, outfile, compression="auto", compresswhol
                 catfp, catoutlist, extradata, fcontents.read(), [checksumtype[1], checksumtype[2]], formatspecs)
             fcontents.close()
         if(numfiles > 0):
-            catfp.write(AppendNullBytes(
-                ["0", "0"], formatspecs['format_delimiter']).encode("UTF-8"))
+            try:
+                catfp.write(AppendNullBytes(
+                    ["0", "0"], formatspecs['format_delimiter']).encode("UTF-8"))
+            except OSError:
+                return False
         if(outfile == "-" or outfile is None or hasattr(outfile, "read") or hasattr(outfile, "write")):
             catfp = CompressArchiveFile(
                 catfp, compression, compressionlevel, formatspecs)
@@ -5943,8 +5967,11 @@ def PackArchiveFileFromSevenZipFile(infile, outfile, compression="auto", compres
                 catfp, catoutlist, extradata, fcontents.read(), [checksumtype[1], checksumtype[2]], formatspecs)
             fcontents.close()
         if(numfiles > 0):
-            catfp.write(AppendNullBytes(
-                ["0", "0"], formatspecs['format_delimiter']).encode("UTF-8"))
+            try:
+                catfp.write(AppendNullBytes(
+                    ["0", "0"], formatspecs['format_delimiter']).encode("UTF-8"))
+            except OSError:
+                return False
         if(outfile == "-" or outfile is None or hasattr(outfile, "read") or hasattr(outfile, "write")):
             catfp = CompressArchiveFile(
                 catfp, compression, compressionlevel, formatspecs)
@@ -9125,8 +9152,11 @@ def RePackArchiveFile(infile, outfile, compression="auto", compresswholefile=Tru
         lcfi = lcfi + 1
         reallcfi = reallcfi + 1
     if(lcfx > 0):
-        catfp.write(AppendNullBytes(
-            ["0", "0"], formatspecs['format_delimiter']).encode("UTF-8"))
+        try:
+            catfp.write(AppendNullBytes(
+                ["0", "0"], formatspecs['format_delimiter']).encode("UTF-8"))
+        except OSError:
+            return False
     if(outfile == "-" or outfile is None or hasattr(outfile, "read") or hasattr(outfile, "write")):
         catfp = CompressArchiveFile(
             catfp, compression, compressionlevel, formatspecs)