diff --git a/core/c/base64.c b/core/c/base64.c
index a37767a9..5ec59496 100644
--- a/core/c/base64.c
+++ b/core/c/base64.c
@@ -57,7 +57,7 @@
 #include "base64.h"
 
 /* aaaack but it's fast and const should make it shared text page. */
-static const unsigned char b64ToBits[256] =
+static const uint8_t b64ToBits[256] =
         {
                 /* ASCII table */
                 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
@@ -97,20 +97,20 @@ int mpw_base64_decode(uint8_t *plainBuf, const char *b64Text) {
     b64Cursor = (uint8_t *)b64Text;
     register uint8_t *plainCursor = plainBuf;
     while (b64Remaining > 4) {
-        *(plainCursor++) = (b64ToBits[b64Cursor[0]] << 2 | b64ToBits[b64Cursor[1]] >> 4);
-        *(plainCursor++) = (b64ToBits[b64Cursor[1]] << 4 | b64ToBits[b64Cursor[2]] >> 2);
-        *(plainCursor++) = (b64ToBits[b64Cursor[2]] << 6 | b64ToBits[b64Cursor[3]]);
+        *(plainCursor++) = (uint8_t)(b64ToBits[b64Cursor[0]] << 2 | b64ToBits[b64Cursor[1]] >> 4);
+        *(plainCursor++) = (uint8_t)(b64ToBits[b64Cursor[1]] << 4 | b64ToBits[b64Cursor[2]] >> 2);
+        *(plainCursor++) = (uint8_t)(b64ToBits[b64Cursor[2]] << 6 | b64ToBits[b64Cursor[3]]);
         b64Cursor += 4;
         b64Remaining -= 4;
     }
 
     /* Note: (b64Size == 1) would be an error, so just ingore that case */
     if (b64Remaining > 1)
-        *(plainCursor++) = (b64ToBits[b64Cursor[0]] << 2 | b64ToBits[b64Cursor[1]] >> 4);
+        *(plainCursor++) = (uint8_t)(b64ToBits[b64Cursor[0]] << 2 | b64ToBits[b64Cursor[1]] >> 4);
     if (b64Remaining > 2)
-        *(plainCursor++) = (b64ToBits[b64Cursor[1]] << 4 | b64ToBits[b64Cursor[2]] >> 2);
+        *(plainCursor++) = (uint8_t)(b64ToBits[b64Cursor[1]] << 4 | b64ToBits[b64Cursor[2]] >> 2);
     if (b64Remaining > 3)
-        *(plainCursor++) = (b64ToBits[b64Cursor[2]] << 6 | b64ToBits[b64Cursor[3]]);
+        *(plainCursor++) = (uint8_t)(b64ToBits[b64Cursor[2]] << 6 | b64ToBits[b64Cursor[3]]);
 
     return (int)(plainCursor - plainBuf);
 }
@@ -126,7 +126,7 @@ size_t mpw_base64_encode_max(size_t plainSize) {
 
 int mpw_base64_encode(char *b64Text, const uint8_t *plainBuf, size_t plainSize) {
 
-    int plainCursor = 0;
+    size_t plainCursor = 0;
     char *b64Cursor = b64Text;
     for (; plainCursor < plainSize - 2; plainCursor += 3) {
         *b64Cursor++ = basis_64[((plainBuf[plainCursor] >> 2)) & 0x3F];
diff --git a/core/c/mpw-marshall-util.c b/core/c/mpw-marshall-util.c
index 5ba22765..cfec3907 100644
--- a/core/c/mpw-marshall-util.c
+++ b/core/c/mpw-marshall-util.c
@@ -76,14 +76,14 @@ const char *mpw_get_json_string(
     return json_object_get_string( json_value );
 }
 
-int32_t mpw_get_json_int(
-        json_object *obj, const char *section, int32_t defaultValue) {
+int64_t mpw_get_json_int(
+        json_object *obj, const char *section, int64_t defaultValue) {
 
     json_object *json_value = mpw_get_json_section( obj, section );
     if (!json_value)
         return defaultValue;
 
-    return json_object_get_int( json_value );
+    return json_object_get_int64( json_value );
 }
 
 bool mpw_get_json_boolean(
diff --git a/core/c/mpw-marshall-util.h b/core/c/mpw-marshall-util.h
index 49a242b3..873be25b 100644
--- a/core/c/mpw-marshall-util.h
+++ b/core/c/mpw-marshall-util.h
@@ -50,8 +50,8 @@ const char *mpw_get_json_string(
 /** Search for an integer in a JSON object tree.
   * @param section A dot-delimited list of JSON object keys to walk toward the child object.
   * @return The integer value or defaultValue if one of the section's object keys was not found in the source object's tree. */
-int32_t mpw_get_json_int(
-        json_object *obj, const char *section, int32_t defaultValue);
+int64_t mpw_get_json_int(
+        json_object *obj, const char *section, int64_t defaultValue);
 /** Search for a boolean in a JSON object tree.
   * @param section A dot-delimited list of JSON object keys to walk toward the child object.
   * @return The boolean value or defaultValue if one of the section's object keys was not found in the source object's tree. */
diff --git a/core/c/mpw-marshall.c b/core/c/mpw-marshall.c
index 303b387a..d8dfe87e 100644
--- a/core/c/mpw-marshall.c
+++ b/core/c/mpw-marshall.c
@@ -187,7 +187,7 @@ static bool mpw_marshall_write_flat(
     }
     mpw_free( masterKey, MPMasterKeySize );
 
-    *error = (MPMarshallError){ MPMarshallSuccess };
+    *error = (MPMarshallError){ .type = MPMarshallSuccess };
     return true;
 }
 
@@ -305,7 +305,7 @@ static bool mpw_marshall_write_json(
     mpw_free( masterKey, MPMasterKeySize );
     json_object_put( json_file );
 
-    *error = (MPMarshallError){ MPMarshallSuccess };
+    *error = (MPMarshallError){ .type = MPMarshallSuccess };
     return true;
 }
 
@@ -537,14 +537,14 @@ static MPMarshalledUser *mpw_marshall_read_flat(
     mpw_free_string( keyID );
     mpw_free( masterKey, MPMasterKeySize );
 
-    *error = (MPMarshallError){ MPMarshallSuccess };
+    *error = (MPMarshallError){ .type = MPMarshallSuccess };
     return user;
 }
 
 static MPMarshalledUser *mpw_marshall_read_json(
         char *in, const char *masterPassword, MPMarshallError *error) {
 
-    *error = (MPMarshallError){ MPMarshallErrorInternal };
+    *error = (MPMarshallError){ MPMarshallErrorInternal, "Unexpected internal error." };
 
     // Parse JSON.
     enum json_tokener_error json_error = json_tokener_success;
@@ -560,7 +560,7 @@ static MPMarshalledUser *mpw_marshall_read_json(
     MPMarshalledUser *user = NULL;
 
     // Section: "export"
-    unsigned int fileFormat = (unsigned int)mpw_get_json_int( json_file, "export.format", 0 );
+    int64_t fileFormat = mpw_get_json_int( json_file, "export.format", 0 );
     if (fileFormat < 1) {
         *error = (MPMarshallError){ MPMarshallErrorFormat, mpw_str( "Unsupported format: %u", fileFormat ) };
         return NULL;
@@ -572,7 +572,7 @@ static MPMarshalledUser *mpw_marshall_read_json(
     const char *fullName = mpw_get_json_string( json_file, "user.full_name", NULL );
     const char *str_lastUsed = mpw_get_json_string( json_file, "user.last_used", NULL );
     const char *keyID = mpw_get_json_string( json_file, "user.key_id", NULL );
-    int32_t value = mpw_get_json_int( json_file, "user.algorithm", MPAlgorithmVersionCurrent );
+    int64_t value = mpw_get_json_int( json_file, "user.algorithm", MPAlgorithmVersionCurrent );
     if (value < MPAlgorithmVersionFirst || value > MPAlgorithmVersionLast) {
         *error = (MPMarshallError){ MPMarshallErrorIllegal, mpw_str( "Invalid user algorithm version: %u", value ) };
         return NULL;
@@ -614,13 +614,13 @@ static MPMarshalledUser *mpw_marshall_read_json(
     json_object *json_sites = mpw_get_json_section( json_file, "sites" );
     json_object_object_foreachC( json_sites, json_site ) {
         const char *siteName = json_site.key;
-        value = mpw_get_json_int( json_site.val, "algorithm", user->algorithm );
+        value = mpw_get_json_int( json_site.val, "algorithm", (int32_t)user->algorithm );
         if (value < MPAlgorithmVersionFirst || value > MPAlgorithmVersionLast) {
             *error = (MPMarshallError){ MPMarshallErrorIllegal, mpw_str( "Invalid site algorithm version: %s: %d", siteName, value ) };
             return NULL;
         }
         MPAlgorithmVersion siteAlgorithm = (MPAlgorithmVersion)value;
-        MPResultType siteType = (MPResultType)mpw_get_json_int( json_site.val, "type", user->defaultType );
+        MPResultType siteType = (MPResultType)mpw_get_json_int( json_site.val, "type", (int32_t)user->defaultType );
         if (!mpw_nameForType( siteType )) {
             *error = (MPMarshallError){ MPMarshallErrorIllegal, mpw_str( "Invalid site type: %s: %u", siteName, siteType ) };
             return NULL;
@@ -679,7 +679,7 @@ static MPMarshalledUser *mpw_marshall_read_json(
     }
     json_object_put( json_file );
 
-    *error = (MPMarshallError){ MPMarshallSuccess };
+    *error = (MPMarshallError){ .type = MPMarshallSuccess };
     return user;
 }
 
diff --git a/core/c/mpw-util.c b/core/c/mpw-util.c
index 8ae61c72..7c05487e 100644
--- a/core/c/mpw-util.c
+++ b/core/c/mpw-util.c
@@ -45,7 +45,7 @@ bool mpw_push_buf(uint8_t **const buffer, size_t *const bufferSize, const void *
 
     if (!buffer || !bufferSize || !pushBuffer || !pushSize)
         return false;
-    if (*bufferSize == ERR)
+    if (*bufferSize == (size_t)ERR)
         // The buffer was marked as broken, it is missing a previous push.  Abort to avoid corrupt content.
         return false;
 
diff --git a/platform-independent/cli-c/cli/mpw-cli.c b/platform-independent/cli-c/cli/mpw-cli.c
index c5cbc42d..ce1f5a4e 100644
--- a/platform-independent/cli-c/cli/mpw-cli.c
+++ b/platform-independent/cli-c/cli/mpw-cli.c
@@ -299,7 +299,7 @@ int main(int argc, char *const argv[]) {
         fclose( sitesFile );
 
         // Parse file.
-        MPMarshallError marshallError = { MPMarshallSuccess };
+        MPMarshallError marshallError = { .type = MPMarshallSuccess };
         user = mpw_marshall_read( buf, sitesFormat, masterPassword, &marshallError );
         if (marshallError.type == MPMarshallErrorMasterPassword) {
             // Incorrect master password.
@@ -550,7 +550,7 @@ int main(int argc, char *const argv[]) {
 
         else {
             char *buf = NULL;
-            MPMarshallError marshallError = { MPMarshallSuccess };
+            MPMarshallError marshallError = { .type = MPMarshallSuccess };
             if (!mpw_marshall_write( &buf, sitesFormat, user, &marshallError ) || marshallError.type != MPMarshallSuccess)
                 wrn( "Couldn't encode updated configuration file:\n  %s: %s\n", sitesPath, marshallError.description );