Those questions cannot be answered by other UltraCompare users with the provided information. Do you know that this is a user to user forum as stated at top of every forum page?
Please report this issue by email to support of UltraEdit, Inc. See the technical support page for more details.
Following information should be in the issue report mail:
Exact version of used UltraCompare as displayed in the About window. The version string can be selected and copied to clipboard with Ctrl+C for pasting it with Ctrl+V into the email.
The kind of operating system (Windows, Mac, Linux of distribution …) and the exact version of the operating system should be also added to the report mail.
On Windows press Windows Logo key + R, enter winver and run this program for getting displayed the Windows version in a graphical window.
The type of the two compared files: binary or text.
Which comparison is executed: binary comparison, text comparison without or with ignore options, table comparison?
In case of comparing to two text files, add the information about the character encoding of each file (ANSI/UTF-8/UTF-16) and the line ending type (DOS/Unix/MAC) to the report.
The used UltraCompare configuration. It is best compressing the entire directory %APPDATA%\IDMComp\UltraCompare into a 7-Zip, RAR or ZIP file and attach this archive file with your configuration to the email. I suggest first making a copy of this directory and open the files uc.ini and uc.vod in subdirectory volatile in a text editor. Then remove or obfuscate all confidential data not being important for reproducing the crash like the histories of the file/folder names. Save the two files, close the text editor and compress that directory copy with all the configuration files no longer containing confidential data into an archive file.
If UltraCompare created a crash dump file, attach this file also to the email (compressed with 7-Zip, RAR or ZIP). If there is no crash dump file created by UltraCompare, add the crash dump file created by Windows (compressed with 7-Zip, RAR or ZIP) and add the application crash information recorded by Windows. Start the Event Viewer, expand Windows Logs and click on Application, wait some seconds until getting displayed the record events, look for the error event record (white exclamation mark in red circle) with the information about the crash of uc.exe and copy and paste the text from both tabs into the email.
Describe step by step your actions resulting finally in the crash of UltraCompare.
As the two compared files are very large, it is for sure not possible to attached them also to the mail. UltraEdit support will reply if more information is needed to reproduce the issue which will be for sure fixed in the next released version of UltraCompare on being reproducible. Issues resulting in a crash of an UltraEdit, Inc. application have always the highest priority.
There can be perhaps also something done by the user depending on version of UltraCompare and type of comparison.
There are options in Configuration under Compare (Default) - Text - Compare like
Logical line matching
Use character to character line comparison
Alignment method
which could be changed and then test if the text file comparison of the huge files does not result in a crash of UltraCompare.
There can be also unchecked the setting Enable syntax coloring at Display - Text - Syntax highlighting in Configuration.
It is also possible to change Scaled/Scrollable Map and other settings at Display - Text - Miscellaneous in Configuration and see if the text comparison does not crash UltraCompare anymore.
Best regards from an UC/UE/UES for Windows user from Austria