diff --git a/reactos/dll/win32/msi/database.c b/reactos/dll/win32/msi/database.c
index cce271769e7..83b1f2ccfbb 100644
--- a/reactos/dll/win32/msi/database.c
+++ b/reactos/dll/win32/msi/database.c
@@ -1206,7 +1206,7 @@ static UINT merge_diff_row(MSIRECORD *rec, LPVOID param)
     MERGETABLE *table = data->curtable;
     MERGEROW *mergerow;
     MSIQUERY *dbview;
-    MSIRECORD *row;
+    MSIRECORD *row = NULL;
     LPWSTR query;
     UINT r;
 
diff --git a/reactos/dll/win32/msi/msi.c b/reactos/dll/win32/msi/msi.c
index 86713fdfabd..9503cf904f0 100644
--- a/reactos/dll/win32/msi/msi.c
+++ b/reactos/dll/win32/msi/msi.c
@@ -1553,7 +1553,7 @@ UINT WINAPI MsiQueryComponentStateW(LPCWSTR szProductCode,
     TRACE("(%s, %s, %d, %s, %p)\n", debugstr_w(szProductCode),
           debugstr_w(szUserSid), dwContext, debugstr_w(szComponent), pdwState);
 
-    if (!pdwState)
+    if (!pdwState || !szComponent)
         return ERROR_INVALID_PARAMETER;
 
     if (!szProductCode || !*szProductCode || lstrlenW(szProductCode) != GUID_SIZE - 1)
diff --git a/reactos/dll/win32/msi/msi.spec b/reactos/dll/win32/msi/msi.spec
index 017fdbe4adb..902e5f80573 100644
--- a/reactos/dll/win32/msi/msi.spec
+++ b/reactos/dll/win32/msi/msi.spec
@@ -250,8 +250,8 @@
 254 stub MsiDeterminePatchSequenceW
 255 stdcall MsiSourceListAddSourceExA(str str long long str long)
 256 stdcall MsiSourceListAddSourceExW(wstr wstr long long wstr long)
-257 stub MsiSourceListClearSourceA
-258 stub MsiSourceListClearSourceW
+257 stdcall MsiSourceListClearSourceA(str str long long str)
+258 stdcall MsiSourceListClearSourceW(wstr wstr long long wstr)
 259 stub MsiSourceListClearAllExA
 260 stub MsiSourceListClearAllExW
 261 stub MsiSourceListForceResolutionExA
diff --git a/reactos/dll/win32/msi/registry.c b/reactos/dll/win32/msi/registry.c
index 9a43b8d1943..36897246ad8 100644
--- a/reactos/dll/win32/msi/registry.c
+++ b/reactos/dll/win32/msi/registry.c
@@ -1894,7 +1894,7 @@ static UINT msi_enum_patches(LPCWSTR szProductCode, LPCWSTR szUserSid,
         MSIINSTALLCONTEXT *pdwTargetProductContext, LPWSTR szTargetUserSid,
         LPDWORD pcchTargetUserSid, LPWSTR *szTransforms)
 {
-    UINT r;
+    UINT r = ERROR_INVALID_PARAMETER;
 
     if (dwContext & MSIINSTALLCONTEXT_USERMANAGED)
     {
diff --git a/reactos/dll/win32/msi/regsvr.c b/reactos/dll/win32/msi/regsvr.c
index bac4eb48e66..abe92cfdf97 100644
--- a/reactos/dll/win32/msi/regsvr.c
+++ b/reactos/dll/win32/msi/regsvr.c
@@ -42,7 +42,6 @@
 #include "initguid.h"
 #include "msipriv.h"
 #include "msiserver.h"
-
 WINE_DEFAULT_DEBUG_CHANNEL(msi);
 
 /*
diff --git a/reactos/dll/win32/msi/source.c b/reactos/dll/win32/msi/source.c
index e8e4a113d5a..8cdaf4001e1 100644
--- a/reactos/dll/win32/msi/source.c
+++ b/reactos/dll/win32/msi/source.c
@@ -1314,3 +1314,27 @@ UINT WINAPI MsiSourceListClearAllW( LPCWSTR szProduct, LPCWSTR szUserName, DWORD
     FIXME("(%s %s %d)\n", debugstr_w(szProduct), debugstr_w(szUserName), dwReserved);
     return ERROR_SUCCESS;
 }
+
+/******************************************************************
+ *  MsiSourceListClearSourceA (MSI.@)
+ */
+UINT WINAPI MsiSourceListClearSourceA(LPCSTR szProductCodeOrPatchCode, LPCSTR szUserSid,
+                                      MSIINSTALLCONTEXT dwContext, DWORD dwOptions,
+                                      LPCSTR szSource)
+{
+    FIXME("(%s %s %x %x %s)\n", debugstr_a(szProductCodeOrPatchCode), debugstr_a(szUserSid),
+          dwContext, dwOptions, debugstr_a(szSource));
+    return ERROR_SUCCESS;
+}
+
+/******************************************************************
+ *  MsiSourceListClearSourceW (MSI.@)
+ */
+UINT WINAPI MsiSourceListClearSourceW(LPCWSTR szProductCodeOrPatchCode, LPCWSTR szUserSid,
+                                      MSIINSTALLCONTEXT dwContext, DWORD dwOptions,
+                                      LPCWSTR szSource)
+{
+    FIXME("(%s %s %x %x %s)\n", debugstr_w(szProductCodeOrPatchCode), debugstr_w(szUserSid),
+          dwContext, dwOptions, debugstr_w(szSource));
+    return ERROR_SUCCESS;
+}
diff --git a/reactos/dll/win32/msi/storages.c b/reactos/dll/win32/msi/storages.c
index 2e21cb87bba..302906b8466 100644
--- a/reactos/dll/win32/msi/storages.c
+++ b/reactos/dll/win32/msi/storages.c
@@ -134,7 +134,7 @@ static UINT STORAGES_get_row( struct tagMSIVIEW *view, UINT row, MSIRECORD **rec
 
 static HRESULT stream_to_storage(IStream *stm, IStorage **stg)
 {
-    ILockBytes *lockbytes;
+    ILockBytes *lockbytes = NULL;
     STATSTG stat;
     LPVOID data;
     HRESULT hr;
@@ -177,7 +177,7 @@ static HRESULT stream_to_storage(IStream *stm, IStorage **stg)
 
 done:
     msi_free(data);
-    ILockBytes_Release(lockbytes);
+    if (lockbytes) ILockBytes_Release(lockbytes);
     return hr;
 }
 
diff --git a/reactos/dll/win32/msi/table.c b/reactos/dll/win32/msi/table.c
index 7cd1c7107b7..e9c2196c163 100644
--- a/reactos/dll/win32/msi/table.c
+++ b/reactos/dll/win32/msi/table.c
@@ -1818,7 +1818,7 @@ static UINT TABLE_remove_column(struct tagMSIVIEW *view, LPCWSTR table, UINT num
 
 done:
     msiobj_release(&rec->hdr);
-    if (columns) columns->ops->delete(columns);
+    columns->ops->delete(columns);
     return r;
 }