NullReferenceException When Moving the Same Email Multiple Times in a PST with Aspose.Email C++

Aspose.Email Product Family
,
1

Hello，

I’m encountering a System::NullReferenceException when repeatedly moving an email within the same PST file using MoveItem() in Aspose.Email for C++. Here are the details:

Environment

  • Aspose.Email for C++ Version: 25.8.0
  • OS: Windows 11
  • PST File Format: Unicode
pst = PersonalStorage::FromFile(System::String::FromUtf8(pstPath.c_str()));
// Find MessageInfo by iterating through folder contents
auto contents = sourceFolder->GetContents();
System::SharedPtr<Aspose::Email::Storage::Pst::MessageInfo> messageInfo = nullptr;
  
if (contents != nullptr) {
  for (int32_t j = 0; j < contents->get_Count(); j++) {
    auto msg = contents->idx_get(j);
    if (msg != nullptr && SystemStringToStdString(msg->get_EntryIdString()) == entryId) {
      messageInfo = msg;
      break;  // Found, exit loop early
    }
  }
}
// takes MessageInfo and target FolderInfo
pst->MoveItem(messageInfo, targetFolder);

When using FolderInfo::MoveItem() to relocate the same email multiple times between folders in the same PST, the following issues occur sequentially:

  1. After 2–3 moves: Attempting to move the email again OR retrieve its details (e.g., MessageInfo->get_Subject(), MessageInfo->get_EntryId(), or extracting the full MapiMessage via PersonalStorage::ExtractMessage()) throws a System::NullReferenceException with the message: “Object reference not set to an instance of an object”.

  2. PST Integrity Impact: To resolve the error, we tried validating/repairing the PST file using Aspose.Email’s PST-related APIs. However, the problematic email is permanently lost after the repair process—it no longer appears in any folder of the PST.

Looking forward to your insights!

2

@liangyongwen

Summary
You are seeing a System::NullReferenceException after moving the same message several times because the MessageInfo instance you keep after the first MoveItem becomes invalid. After a move the underlying PST entry is removed from the source folder and the wrapper object no longer points to a valid native object, so any subsequent property access (e.g., get_Subject(), get_EntryId()) throws the exception. The PST file itself is not corrupted; the loss of the message after running ValidateAndRepair is a side‑effect of trying to repair a reference that no longer exists.

Why it happens

Cause Explanation
Stale MessageInfo PersonalStorage::MoveItem(messageInfo, targetFolder) moves the item and disposes the original entry. The MessageInfo you still hold still points to the now‑deleted native object, so accessing it results in a null reference.
Folder cache not refreshed The folder’s content collection is cached. If you reuse the same MessageInfoCollection after a move, the library may return a null entry because the cache was not rebuilt.
Repair treats the dangling reference as corrupted ValidateAndRepair sees the invalid reference and removes it, which is why the message disappears from all folders.

What to do next

  1. Never reuse the same MessageInfo after a move – obtain a fresh reference from the target folder each time you need to work with the message.
// Move the item
pst->MoveItem(messageInfo, targetFolder);

// Refresh the target folder and get a new MessageInfo
auto refreshedContents = targetFolder->GetContents();
System::SharedPtr<Aspose::Email::Storage::Pst::MessageInfo> freshInfo = nullptr;
for (int i = 0; i < refreshedContents->get_Count(); ++i) {
auto mi = refreshedContents->idx_get(i);
if (mi != nullptr && SystemStringToStdString(mi->get_EntryIdString()) == entryId) {
freshInfo = mi;
break;
}
}
// Use freshInfo for any further operations
  1. Refresh folder contents before each lookup – call GetContents() on the source or target folder after every move instead of keeping a long‑lived MessageInfoCollection.
  2. Wrap move operations in try‑catch to log any unexpected exceptions and confirm that the null reference originates from a stale object.
try {
pst->MoveItem(messageInfo, targetFolder);
} catch (System::Exception^ ex) {
Console::WriteLine("Move failed: {0}", ex->Message);
}
  1. Avoid running ValidateAndRepair after the exception – the repair routine will treat the already‑invalid reference as corrupted and delete the message. Prevent the exception by always using a fresh MessageInfo.
  2. Test with a minimal PST – create a small PST (5‑10 messages) and write a loop that moves the same message back and forth, re‑querying the folder after each move. Verify that no exception occurs when you follow the refresh pattern.
  3. Consider upgrading – later releases of Aspose.Email for C++ contain fixes for PST handling. If the problem persists after applying the above pattern, try a newer version and report the behavior to Aspose support with a reproducible sample.
  4. If the issue still appears – capture the full exception details (message, stack trace, method name) and provide a sanitized PST along with the code snippet to Aspose engineering for deeper investigation.

Quick checklist

  • [ ] After each MoveItem, call GetContents() on the target folder.
  • [ ] Locate the moved message again and store the new MessageInfo.
  • [ ] Do not use the original MessageInfo for any further operation.
  • [ ] Log exceptions with stack trace.
  • [ ] Test with a fresh PST and, if possible, with a newer library version.

Following these steps should prevent the NullReferenceException and keep the message intact during multiple moves. If you continue to experience problems, gather the details listed above and share them with Aspose support for further analysis.

Note: The answer is based on typical behavior of the Aspose.Email for C++ API. The specific evidence retrieved does not directly cover this scenario, so the explanation reflects known usage patterns and best practices rather than a documented bug.

:warning: I could not fully verify this explanation against the retrieved sources. Please double-check the behaviour in your environment and confirm the exact SDK/version.