diff --git a/indra/llcommon/llapr.cpp b/indra/llcommon/llapr.cpp
index de7f3e9dc..a1a445261 100644
--- a/indra/llcommon/llapr.cpp
+++ b/indra/llcommon/llapr.cpp
@@ -29,6 +29,7 @@
 #include "linden_common.h"
 #include "llapr.h"
 #include "llscopedvolatileaprpool.h"
+#include <limits>
 
 bool ll_apr_warn_status(apr_status_t status)
 {
@@ -150,7 +151,7 @@ apr_status_t LLAPRFile::open(const std::string& filename, apr_int32_t flags, BOO
 	return open(filename, flags, use_global_pool ? LLAPRFile::long_lived : LLAPRFile::short_lived);
 }
 // File I/O
-S32 LLAPRFile::read(void *buf, S32 nbytes)
+S32 LLAPRFile::read(void *buf, U64 nbytes)
 {
 	if(!mFile) 
 	{
@@ -167,12 +168,12 @@ S32 LLAPRFile::read(void *buf, S32 nbytes)
 	}
 	else
 	{
-		llassert_always(sz <= 0x7fffffff);
+		llassert_always(sz <= std::numeric_limits<apr_size_t>::max());
 		return (S32)sz;
 	}
 }
 
-S32 LLAPRFile::write(const void *buf, S32 nbytes)
+S32 LLAPRFile::write(const void *buf, U64 nbytes)
 {
 	if(!mFile) 
 	{
@@ -189,7 +190,7 @@ S32 LLAPRFile::write(const void *buf, S32 nbytes)
 	}
 	else
 	{
-		llassert_always(sz <= 0x7fffffff);
+		llassert_always(sz <= std::numeric_limits<apr_size_t>::max());
 		return (S32)sz;
 	}
 }
diff --git a/indra/llcommon/llapr.h b/indra/llcommon/llapr.h
index 9baddef5f..0363a8faf 100644
--- a/indra/llcommon/llapr.h
+++ b/indra/llcommon/llapr.h
@@ -92,8 +92,8 @@ public:
 	apr_status_t eof() { return apr_file_eof(mFile);}
 
 	// Returns bytes read/written, 0 if read/write fails:
-	S32 read(void* buf, S32 nbytes);
-	S32 write(const void* buf, S32 nbytes);
+	S32 read(void* buf, U64 nbytes);
+	S32 write(const void* buf, U64 nbytes);
 	
 	apr_file_t* getFileHandle() {return mFile;}	
 
diff --git a/indra/newview/lltexturecache.cpp b/indra/newview/lltexturecache.cpp
index 7e4ed1ad3..ed878a02f 100644
--- a/indra/newview/lltexturecache.cpp
+++ b/indra/newview/lltexturecache.cpp
@@ -1305,14 +1305,12 @@ void LLTextureCache::writeEntriesAndClose(const std::vector<Entry>& entries)
 	if (!mReadOnly)
 	{
 		LLAPRFile* aprfile = openHeaderEntriesFile(false, (S32)sizeof(EntriesInfo));
-		for (S32 idx=0; idx<num_entries; idx++)
+		U64 write_size = U64(sizeof(Entry)) * num_entries;
+		U64 bytes_written = aprfile->write((void*)(entries.data()), write_size);
+		if (bytes_written != write_size)
 		{
-			S32 bytes_written = aprfile->write((void*)(&entries[idx]), (S32)sizeof(Entry));
-			if(bytes_written != sizeof(Entry))
-			{
-				clearCorruptedCache(); //clear the cache.
-				return;
-			}
+			clearCorruptedCache(); //clear the cache.
+			return;
 		}
 		closeHeaderEntriesFile();
 	}