Created attachment 38595 [details]
This attachment shows the error

Hi
I am using apche poi ooxm-5.2.3 version and i was tried older version also.
I have used apache poi for reading the xlsx sheets and removing the selected tabs that is working fine after deletion the save not happen it throwing the following error.

org.apache.poi.openxml4j.exceptions.InvalidOperationException: A part with the name '/docProps/core.xml' already exists : Packages shall not contain equivalent part names and package implementers shall neither create nor recognize packages with equivalent part names. [M1.12]
	at org.apache.poi.openxml4j.opc.OPCPackage.addPackagePart(OPCPackage.java:947)
	at org.apache.poi.openxml4j.opc.ZipPackage.saveImpl(ZipPackage.java:547)
	at org.apache.poi.openxml4j.opc.OPCPackage.save(OPCPackage.java:1496)
	at org.apache.poi.ooxml.POIXMLDocument.write(POIXMLDocument.java:227)
	at com.simplilearn.mavenexample.Authentication.getWorkbook(Authentication.java:691)
	at com.simplilearn.mavenexample.Authentication.exportToFile(Authentication.java:656)
	at com.simplilearn.mavenexample.App.main(App.java:29)

So as per my understanding whenever edit happens using the apche poi it try to create new OPC package part  checks existing part so that time the error displayed.

For testing purpose i have deleted the package part then it was allowed for SAVE.

The JAVA code is pretty straight forward.

try {
		ByteArrayOutputStream bos = new ByteArrayOutputStream();
		XSSFWorkbook testWorkBook = new XSSFWorkbook(inputfile);
		testWorkBook.removeSheetAt(0);
		testWorkBook.write(bos);
		}
		catch(Exception e) {
			e.printStackTrace();
		}

Observations:
1.Once opened XLSX even without change also not allowed for save
2.The part name removal working only for windows Environment not LINUX server