Both XML files can be reformatted perfect by UltraEdit on Windows (v26.20.0.46 and v22.20.0.49) without any issue. The UTF-8 encoding is also correct in both files.

You could be right regarding to line length. It looks like newline characters where inserted after X bytes resulting in wrong lines in reformatted XML and also in invalid UTF-8 encoded characters.

I suggest top open in UltraEdit Advanced - Settings or Configuration - Editor - Word wrap / tab settings and make sure that for all file extensions (Default in drop down list and perhaps others configured by you) the setting Default word wrap on for each file is not checked or at least Wrap after column #, insert CR/LF is not selected which inserts newline characters on enabling word wrap for active file respectively inserts newline characters already on opening a file with word wrap enabled for each each file and this word wrap mode selected and Automatically insert CR/LF when file is opened additionally checked.

UltraEdit inserts carriage return + line-feed into a DOS/Windows file (or just line-feed into a Unix file) only when word wrap is enabled with Wrap after column #, insert CR/LF selected for active file according to its file extension as displayed in drop down list above whereby Default means for all files with no file extension or a file extension for which no separate configuration exists.

Inserting newline characters immediately on opening a file is done only by UltraEdit on having enabled Default word wrap on for each file, having selected Wrap after column #, insert CR/LF and having enabled Automatically insert CR/LF when file is opened. In all other cases a file is opened either unwrapped or just soft wrapped which means lines are wrapped for display in the window, but file content is not changed by UltraEdit.

Well, there is additionally Maximum columns before line wraps in configuration at Editor display - Miscellaneous. But lines wrapped because of this configuration are just wrapped in window. There is not made any modification on file content by the line wrapping done because of this configuration setting.

There is also Reformat paragraph after paste when wrap settings set to add hard returns at specific column number in configuration at Editor display - Formatting. But this option is only active if word wrap is enabled for active file and inserts newline characters only if selected word wrap method is Wrap after column #, insert CR/LF.

It looks like your configuration is the default configuration for 64-bit UltraEdit for Windows.

I used your configuration with 32-bit and with 64-bit English UltraEdit for Windows v26.20.0.46 on English Windows 7 SP1 x64.

Sorry, but I could not reproduce a wrong formatting of the two provided sample XML files using Coding - XML - Reformat XML.

I copied the not formatted XML data and pasted them into a new ANSI file on which UltraEdit prompted me to convert the file first to UTF-8 because of detecting that clipboard contains UTF-8 encoded text, which I confirmed, and next reformatted the XML data with getting a correct result. I copied and pasted not formatted and UTF-8 encoded XML data also into a new UTF-16 LE encoded file, reformatted the XML data in UTF-16 LE encoded file, and got once again the XML data correct reformatted without unexpected line breaks as in your screenshot.

Sorry, I have no more idea what could cause the wrong XML reformatting on your Windows computer. I can only suppose that there is something affecting the XML reformatting task not stored in INI file of UltraEdit like a Windows setting because of not using an English Windows or in program files of UltraEdit on using Chinese UltraEdit. Your Windows account name is definitely no problem. The path to temporary files directory does not contain Unicode characters.

It is good to know in which environment the XML reformatting does not work as it should. I suggest that you report this issue to IDM support by email. The email address can be found for example on technical support page. Attach one of the two XML files and the screenshot showing the wrong result after reformatting the attached XML file on Chinese Windows 10. Don't forget to write that this issue occurs only on Chinese Windows 10 with English and simplified Chinese version of 64-bit UltraEdit v26.20.0.46.