diff --git a/include/downloader.h b/include/downloader.h
index 3f676da..e4287fc 100644
--- a/include/downloader.h
+++ b/include/downloader.h
@@ -74,7 +74,7 @@ class Downloader
         Timer timer;
         Config config;
         ProgressBar* progressbar;
-        std::deque< std::pair<time_t, size_t> > TimeAndSize;
+        std::deque< std::pair<time_t, uintmax_t> > TimeAndSize;
     protected:
     private:
         CURLcode downloadFile(const std::string& url, const std::string& filepath, const std::string& xml_data = std::string(), const std::string& gamename = std::string());
@@ -82,7 +82,7 @@ class Downloader
         int downloadCovers(const std::string& gamename, const std::string& directory, const std::string& cover_xml_data);
         int getGameDetails();
         void getGameList();
-        size_t getResumePosition();
+        uintmax_t getResumePosition();
         CURLcode beginDownload();
         std::string getResponse(const std::string& url);
         std::string getLocalFileHash(const std::string& filepath, const std::string& gamename = std::string());
@@ -99,9 +99,9 @@ class Downloader
         void saveSerials(const std::string& serials, const std::string& filepath);
 
         static int progressCallback(void *clientp, double dltotal, double dlnow, double ultotal, double ulnow);
-        static size_t writeMemoryCallback(char *ptr, size_t size, size_t nmemb, void *userp);
-        static size_t writeData(void *ptr, size_t size, size_t nmemb, FILE *stream);
-        static size_t readData(void *ptr, size_t size, size_t nmemb, FILE *stream);
+        static uintmax_t writeMemoryCallback(char *ptr, uintmax_t size, uintmax_t nmemb, void *userp);
+        static uintmax_t writeData(void *ptr, uintmax_t size, uintmax_t nmemb, FILE *stream);
+        static uintmax_t readData(void *ptr, uintmax_t size, uintmax_t nmemb, FILE *stream);
 
 
         API *gogAPI;
@@ -109,7 +109,7 @@ class Downloader
         std::vector<gameDetails> games;
         std::string coverXML;
 
-        size_t resume_position;
+        uintmax_t resume_position;
         int retries;
         std::ofstream report_ofs;
 };
diff --git a/include/util.h b/include/util.h
index 25e9f78..f6904dc 100644
--- a/include/util.h
+++ b/include/util.h
@@ -32,7 +32,7 @@ namespace Util
     std::string makeFilepath(const std::string& directory, const std::string& path, const std::string& gamename, std::string subdirectory = "", const unsigned int& platformId = 0, const std::string& dlcname = "");
     std::string makeRelativeFilepath(const std::string& path, const std::string& gamename, std::string subdirectory = "");
     std::string getFileHash(const std::string& filename, unsigned hash_id);
-    std::string getChunkHash(unsigned char* chunk, size_t chunk_size, unsigned hash_id);
+    std::string getChunkHash(unsigned char* chunk, uintmax_t chunk_size, unsigned hash_id);
     int createXML(std::string filepath, size_t chunk_size, std::string xml_dir = std::string());
     int getGameSpecificConfig(std::string gamename, gameSpecificConfig* conf, std::string directory = std::string());
     int replaceString(std::string& str, const std::string& to_replace, const std::string& replace_with);
diff --git a/src/downloader.cpp b/src/downloader.cpp
index 684c1be..f784886 100644
--- a/src/downloader.cpp
+++ b/src/downloader.cpp
@@ -1158,7 +1158,7 @@ CURLcode Downloader::downloadFile(const std::string& url, const std::string& fil
     CURLcode res = CURLE_RECV_ERROR; // assume network error
     bool bResume = false;
     FILE *outfile;
-    size_t offset=0;
+    uintmax_t offset=0;
 
     // Get directory from filepath
     boost::filesystem::path pathname = filepath;
@@ -1226,7 +1226,7 @@ CURLcode Downloader::downloadFile(const std::string& url, const std::string& fil
                 bResume = true;
                 fseek(outfile, 0, SEEK_END);
                 offset = ftell(outfile);
-                curl_easy_setopt(curlhandle, CURLOPT_RESUME_FROM, offset);
+                curl_easy_setopt(curlhandle, CURLOPT_RESUME_FROM_LARGE, offset);
                 this->resume_position = offset;
             }
             else
@@ -1366,10 +1366,10 @@ int Downloader::repairFile(const std::string& url, const std::string& filepath,
 {
     int res = 0;
     FILE *outfile;
-    size_t offset=0, from_offset, to_offset, filesize;
+    uintmax_t offset=0, from_offset, to_offset, filesize;
     std::string filehash;
     int chunks;
-    std::vector<size_t> chunk_from, chunk_to;
+    std::vector<uintmax_t> chunk_from, chunk_to;
     std::vector<std::string> chunk_hash;
     bool bParsingFailed = false;
 
@@ -1561,9 +1561,9 @@ int Downloader::repairFile(const std::string& url, const std::string& filepath,
     int iChunksRepaired = 0;
     for (int i=0; i<chunks; i++)
     {
-        size_t chunk_begin = chunk_from.at(i);
-        size_t chunk_end = chunk_to.at(i);
-        size_t size=0, chunk_size = chunk_end - chunk_begin + 1;
+        uintmax_t chunk_begin = chunk_from.at(i);
+        uintmax_t chunk_end = chunk_to.at(i);
+        uintmax_t size=0, chunk_size = chunk_end - chunk_begin + 1;
         std::string range = std::to_string(chunk_begin) + "-" + std::to_string(chunk_end); // Download range string for curl
 
         std::cout << "\033[0K\rChunk " << i << " (" << chunk_size << " bytes): ";
@@ -1799,7 +1799,7 @@ int Downloader::progressCallback(void *clientp, double dltotal, double dlnow, do
 
         // 10 second average download speed
         // Don't use static value of 10 seconds because update interval depends on when and how often progress callback is called
-        downloader->TimeAndSize.push_back(std::make_pair(time(NULL), static_cast<size_t>(dlnow)));
+        downloader->TimeAndSize.push_back(std::make_pair(time(NULL), static_cast<uintmax_t>(dlnow)));
         if (downloader->TimeAndSize.size() > 100) // 100 * 100ms = 10s
         {
             downloader->TimeAndSize.pop_front();
@@ -1870,24 +1870,24 @@ int Downloader::progressCallback(void *clientp, double dltotal, double dlnow, do
     return 0;
 }
 
-size_t Downloader::writeMemoryCallback(char *ptr, size_t size, size_t nmemb, void *userp) {
+uintmax_t Downloader::writeMemoryCallback(char *ptr, uintmax_t size, uintmax_t nmemb, void *userp) {
     std::ostringstream *stream = (std::ostringstream*)userp;
-    size_t count = size * nmemb;
+    uintmax_t count = size * nmemb;
     stream->write(ptr, count);
     return count;
 }
 
-size_t Downloader::writeData(void *ptr, size_t size, size_t nmemb, FILE *stream)
+uintmax_t Downloader::writeData(void *ptr, uintmax_t size, uintmax_t nmemb, FILE *stream)
 {
     return fwrite(ptr, size, nmemb, stream);
 }
 
-size_t Downloader::readData(void *ptr, size_t size, size_t nmemb, FILE *stream)
+uintmax_t Downloader::readData(void *ptr, uintmax_t size, uintmax_t nmemb, FILE *stream)
 {
     return fread(ptr, size, nmemb, stream);
 }
 
-size_t Downloader::getResumePosition()
+uintmax_t Downloader::getResumePosition()
 {
     return this->resume_position;
 }
diff --git a/src/util.cpp b/src/util.cpp
index 2d57807..40e5208 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -71,7 +71,7 @@ std::string Util::getFileHash(const std::string& filename, unsigned hash_id)
     return result;
 }
 
-std::string Util::getChunkHash(unsigned char *chunk, size_t chunk_size, unsigned hash_id)
+std::string Util::getChunkHash(unsigned char *chunk, uintmax_t chunk_size, unsigned hash_id)
 {
     unsigned char digest[rhash_get_digest_size(hash_id)];
     char result[rhash_get_hash_length(hash_id)];
@@ -87,12 +87,12 @@ std::string Util::getChunkHash(unsigned char *chunk, size_t chunk_size, unsigned
 }
 
 // Create GOG XML
-int Util::createXML(std::string filepath, size_t chunk_size, std::string xml_dir)
+int Util::createXML(std::string filepath, uintmax_t chunk_size, std::string xml_dir)
 {
     int res = 0;
     FILE *infile;
     FILE *xmlfile;
-    size_t filesize, size;
+    uintmax_t filesize, size;
     int chunks, i;
 
     if (xml_dir.empty())
@@ -158,11 +158,11 @@ int Util::createXML(std::string filepath, size_t chunk_size, std::string xml_dir
     char rhash_result[rhash_get_hash_length(RHASH_MD5)];
 
     for (i = 0; i < chunks; i++) {
-        size_t range_begin = i*chunk_size;
+        uintmax_t range_begin = i*chunk_size;
         fseek(infile, range_begin, SEEK_SET);
         if ((i == chunks-1) && (remaining != 0))
             chunk_size = remaining;
-        size_t range_end = range_begin + chunk_size - 1;
+        uintmax_t range_end = range_begin + chunk_size - 1;
         unsigned char *chunk = (unsigned char *) malloc(chunk_size * sizeof(unsigned char *));
         if (chunk == NULL)
         {