It is really impossible to append more than 255 chars into a single cell by VBA macro in MS Excel?
Sample code:
Option Explicit
Sub TestSub()
Dim L
I think that this is due to Excel. Mr. Microsoft : "If you use a Microsoft Visual Basic for Applications procedure to pass a string that is greater than 255 characters in length to an object, such as a text box, Microsoft Excel may truncate the string to 255 characters or may fail to enter the string in the text box. "
Even though you are not passing a more than 255 characters string, I think this is related
https://support.microsoft.com/en-us/kb/213841
They offer a workaround on that support page.