Below is error am facing when loading epub file in pagina EPUB checker.

EPUBCheck aborted! The system lacks sufficient memory! Make sure that Java is installed as 64bit application. Error code: 99

Please let me know if there is solution for it.

Regards, Anil

  • What OS what type of CPU What version of Java? How do you call EpubChecker? What is pagina EPUB checker? I assume EPUBCheck is w3.org/publishing/epubcheck
    – mmmmmm
    Feb 1, 2022 at 14:59

2 Answers 2


Java applications can be started using a command line argument to specify the maximum amount of memory to allocate.

For example, DocFetrcher on a particular Windows PC uses a batch file with the following arguments:

java -enableassertions -Xmx1g -Xss2m -cp %libclasspath% -Djava.library.path=lib net.sourceforge.docfetcher.Main %1 %2 %3 %4 %5 %6 %7 %8 %9

-Xmx1g (or -Xmx1G) specifies 1 gigabyte as the maximum heap size

-Xss2m (or -Xss2M) specifies 2 megabytes as the maximum Java thread stack size

Consider experimenting with variously sized batch startup files for EPUBCheck, and consult with their tech support for help on that.


When I run epubcheck via command line on Windows with java installed, I used to get those error messages. Then following some release notes for epubcheck, I began to run the command this way:

java -Xss1024k -jar epubcheck.jar myebook.epub

From that point, it worked correctly every time.

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