diff --git a/src/bench/base58.cpp b/src/bench/base58.cpp
index 65e27a615d934..c74a958c8b179 100644
--- a/src/bench/base58.cpp
+++ b/src/bench/base58.cpp
@@ -22,7 +22,7 @@ static void Base58Encode(benchmark::State& state)
         }
     };
     while (state.KeepRunning()) {
-        EncodeBase58(buff.begin(), buff.end());
+        EncodeBase58(buff.data(), buff.data() + buff.size());
     }
 }
 
diff --git a/src/bench/checkqueue.cpp b/src/bench/checkqueue.cpp
index b7ae5c2d572d4..94064c9ca67c9 100644
--- a/src/bench/checkqueue.cpp
+++ b/src/bench/checkqueue.cpp
@@ -19,7 +19,7 @@ static const int MIN_CORES = 2;
 static const size_t BATCHES = 101;
 static const size_t BATCH_SIZE = 30;
 static const int PREVECTOR_SIZE = 28;
-static const int QUEUE_BATCH_SIZE = 128;
+static const unsigned int QUEUE_BATCH_SIZE = 128;
 static void CCheckQueueSpeed(benchmark::State& state)
 {
     struct FakeJobNoWork {
diff --git a/src/chainparams.cpp b/src/chainparams.cpp
index 299a3795ce43f..70e7fdf9d05ab 100644
--- a/src/chainparams.cpp
+++ b/src/chainparams.cpp
@@ -404,7 +404,7 @@ class CMainParams : public CChainParams {
         nMinSporkKeys = 1;
         fBIP9CheckMasternodesUpgraded = true;
 
-        checkpointData = (CCheckpointData) {
+        checkpointData = {
             {
                 {1500, uint256S("0x000000aaf0300f59f49bc3e970bad15c11f961fe2347accffff19d96ec9778e3")},
                 {4991, uint256S("0x000000003b01809551952460744d5dbb8fcbd6cbae3c220267bf7fa43f837367")},
@@ -580,7 +580,7 @@ class CTestNetParams : public CChainParams {
         nMinSporkKeys = 1;
         fBIP9CheckMasternodesUpgraded = true;
 
-        checkpointData = (CCheckpointData) {
+        checkpointData = {
             {
                 {261, uint256S("0x00000c26026d0815a7e2ce4fa270775f61403c040647ff2c3091f99e894a4618")},
                 {1999, uint256S("0x00000052e538d27fa53693efe6fb6892a0c1d26c0235f599171c48a3cce553b1")},
@@ -848,7 +848,7 @@ class CRegTestParams : public CChainParams {
         // regtest usually has no masternodes in most tests, so don't check for upgraged MNs
         fBIP9CheckMasternodesUpgraded = false;
 
-        checkpointData = (CCheckpointData) {
+        checkpointData = {
             {
                 {0, uint256S("0x000008ca1832a4baf228eb1553c03d3a2c8e02399550dd6ea8d65cec3ef23d2e")},
             }
diff --git a/src/compat.h b/src/compat.h
index bc59357435c2d..799aff55709ab 100644
--- a/src/compat.h
+++ b/src/compat.h
@@ -41,6 +41,7 @@
 #include <mswsock.h>
 #include <windows.h>
 #include <ws2tcpip.h>
+#include <stdint.h>
 #else
 #include <fcntl.h>
 #include <sys/mman.h>
@@ -81,6 +82,15 @@ typedef unsigned int SOCKET;
 #else
 #define MAX_PATH            1024
 #endif
+#ifdef _MSC_VER
+#if !defined(ssize_t)
+#ifdef _WIN64
+typedef int64_t ssize_t;
+#else
+typedef int32_t ssize_t;
+#endif
+#endif
+#endif
 
 #if HAVE_DECL_STRNLEN == 0
 size_t strnlen( const char *start, size_t max_len);
diff --git a/src/net_processing.cpp b/src/net_processing.cpp
index 1042ba6a9a5f9..553d2c74813c7 100644
--- a/src/net_processing.cpp
+++ b/src/net_processing.cpp
@@ -64,7 +64,7 @@ std::atomic<int64_t> nTimeBestReceived(0); // Used only to inform the wallet of
 struct IteratorComparator
 {
     template<typename I>
-    bool operator()(const I& a, const I& b)
+    bool operator()(const I& a, const I& b) const
     {
         return &(*a) < &(*b);
     }
diff --git a/src/random.h b/src/random.h
index 60fa404758c37..059a552803505 100644
--- a/src/random.h
+++ b/src/random.h
@@ -138,7 +138,7 @@ class FastRandomContext {
  * sure that the underlying OS APIs for all platforms support the number.
  * (many cap out at 256 bytes).
  */
-static const ssize_t NUM_OS_RANDOM_BYTES = 32;
+static const int NUM_OS_RANDOM_BYTES = 32;
 
 /** Get 32 bytes of system entropy. Do not use this in application code: use
  * GetStrongRandBytes instead.
diff --git a/src/support/cleanse.cpp b/src/support/cleanse.cpp
index 95899c9f02d96..eb6e0a73a2082 100644
--- a/src/support/cleanse.cpp
+++ b/src/support/cleanse.cpp
@@ -7,6 +7,10 @@
 
 #include <cstring>
 
+#if defined(_MSC_VER)
+#include <Windows.h> // For SecureZeroMemory.
+#endif
+
 /* Compilers have a bad habit of removing "superfluous" memset calls that
  * are trying to zero memory. For example, when memset()ing a buffer and
  * then free()ing it, the compiler might decide that the memset is
@@ -32,7 +36,7 @@ void memory_cleanse(void *ptr, size_t len)
        might try to eliminate "superfluous" memsets. If there's an easy way to
        detect memset_s, it would be better to use that. */
 #if defined(_MSC_VER)
-    __asm;
+    SecureZeroMemory(ptr, len);
 #else
     __asm__ __volatile__("" : : "r"(ptr) : "memory");
 #endif
diff --git a/src/test/checkqueue_tests.cpp b/src/test/checkqueue_tests.cpp
index 185c5bd3973d6..0ada66a3b5575 100644
--- a/src/test/checkqueue_tests.cpp
+++ b/src/test/checkqueue_tests.cpp
@@ -24,7 +24,7 @@
 // otherwise.
 BOOST_FIXTURE_TEST_SUITE(checkqueue_tests, TestingSetup)
 
-static const int QUEUE_BATCH_SIZE = 128;
+static const unsigned int QUEUE_BATCH_SIZE = 128;
 
 struct FakeCheck {
     bool operator()()