Adding custom icons to files on desktop crashes explorer.exe

[mstybay]

Version of SharpShell used: 2.7.2

I have a Windows service application to add custom icons to files and directories using .Net Framework 4.5.2.
When I try to create a Microsoft Excel file on desktop, file icon moves to default file position on the desktop (top left).
If I create any other type of file (e.g. Microsoft Word), file gets created at the exact location where I clicked.
And if I create multiple Microsoft Excel files consecutively, explorer.exe crashes and restarts.
What can I do about it?