diff --git a/src/ExternalConnector.cpp b/src/ExternalConnector.cpp
index 7a9766e78e..5374f30d21 100644
--- a/src/ExternalConnector.cpp
+++ b/src/ExternalConnector.cpp
@@ -244,7 +244,7 @@ char *command_completion(const char *text, int state)
 	}
 
 	wxString test(wxString(text, *wxConvCurrent).Lower());
-	while (nextCommand != curCommands->end()) {
+	while (curCommands && (nextCommand != curCommands->end())) {
 		wxString curTest = (*nextCommand)->GetCommand();
 		++nextCommand;
 		if (curTest.Lower().StartsWith(test)) {
diff --git a/src/KnownFile.cpp b/src/KnownFile.cpp
index 576330060d..bec98ef7b4 100644
--- a/src/KnownFile.cpp
+++ b/src/KnownFile.cpp
@@ -1153,7 +1153,7 @@ void CKnownFile::CreateOfferedFilePacket(
 					tags.push_back(new CTagInt32(FT_FILESIZE_HI, (uint32)(GetFileSize() >> 32)));
 				}
 			} else {
-				if (!pClient->SupportsLargeFiles()) {
+				if (pClient && (!pClient->SupportsLargeFiles())) {
 					wxFAIL;
 					tags.push_back(new CTagInt32(FT_FILESIZE, 0));
 				} else {
diff --git a/src/SharedFileList.cpp b/src/SharedFileList.cpp
index 97a8eec03e..be0bdf3b08 100644
--- a/src/SharedFileList.cpp
+++ b/src/SharedFileList.cpp
@@ -745,7 +745,7 @@ void CSharedFileList::SendListToServer(){
 	//   - this function is called once when connecting to a server and when a file becomes shareable - so, it's called rarely.
 	//   - if the compressed size is still >= the original size, we send the uncompressed packet
 	// therefor we always try to compress the packet
-	if (server->GetTCPFlags() & SRV_TCPFLG_COMPRESSION){
+	if (server && (server->GetTCPFlags() & SRV_TCPFLG_COMPRESSION)){
 		packet->PackPacket();
 	}