Is it possible to generate an Excel report from Sentinel Monitoring Plus with more than 65535 lines?

It is not possible to generate an Excel report with more than 65535 lines. Also Sentinel is not able to detect the issue.

Also note Excel 2003 can also not open a file with more than 65535 lines. The solution is to upgrade to Excel 2007

A workaround is to use oher formats(pdf, csv, ...)
Also note it's possible to generate an excel file from a csv file

If you want to create an Excel 2007 report from CSV file these are the steps(you cannot simply open the CSV file because data will be wrongly interpreted) :
1) Open Excel 2007 with an empty worksheet;
2)  Click on "Data", then click the "From Text" button in the "Get External Data" menu..
This will bring up the "Import Text File" dialog. Choose the file and the press the "Import" button.
After this the "Text Import Wizard" will be opened.
3) In the first step (step 1 of 3) choose the option "Delimited" under the tab "Original data type". Press the "Next" button.
4) In the second step (step 2 of 3) under the tab "Delimiters" choose "Comma" option. You will see in the preview that data will be imported correctly. Choose also the option "Treat consecutive delimiters as one". Press the "Next" button
5) In the third step (step 3 of 3) you can choose for each column a format or simply press the "Finish" button.