diff --git a/src/common/wfstream.cpp b/src/common/wfstream.cpp
index e40bc2fcfa..59d89d127e 100644
--- a/src/common/wfstream.cpp
+++ b/src/common/wfstream.cpp
@@ -236,7 +236,8 @@ size_t wxFFileInputStream::OnSysRead(void *buffer, size_t size)
 {
     ssize_t ret = m_file->Read(buffer, size);
 
-    if (m_file->Eof())
+    // It is not safe to call Eof() if the file is not opened.
+    if (!m_file->IsOpened() || m_file->Eof())
         m_lasterror = wxSTREAM_EOF;
     if (ret == wxInvalidOffset)
     {
@@ -314,7 +315,8 @@ wxFFileOutputStream::~wxFFileOutputStream()
 size_t wxFFileOutputStream::OnSysWrite(const void *buffer, size_t size)
 {
     size_t ret = m_file->Write(buffer, size);
-    if (m_file->Error())
+    // It is not safe to call Error() if the file is not opened.
+    if (!m_file->IsOpened() || m_file->Error())
         m_lasterror = wxSTREAM_WRITE_ERROR;
     else
         m_lasterror = wxSTREAM_NO_ERROR;