Files ending in XLB are used by the Microsoft Excel for Toolbars spreadsheet. Toolbars, which are also called Command Bars, are called toolbars in the German version.
The XLB files contain settings for these toolbars such as their position and arrangement as well as other parameters. The XLB files allow the transfer of custom or customized toolbars.
By default, the files are stored in the [username] Application DataMicrosoftExcel directory.
Older versions of Microsoft Excel for Apple Mac use this extension to extend the version number of Excel, such as Xlb4 for Excel 4.
Most often resolving problems with opening XLB files is very simple. Just install an appropriate program that supports such files. All of the listed programs support XLB files, but may vary in offered function and purpose. Some programs may be capable only of viewing contents of XLB files or offer file conversion options, but may not be capable of editing such files.
It is possible that although a compatible program has been installed on user’s system, it is not used by the system to open it. This may happen because no default application was associated with this type of files. To associate XLB files with given application, select "Open with" from drop-down menu (accessed by right-clicking on the file). Then select from the list the program or application you want to be used to open this type of file. If the Microsoft Excel applications is not on the list, select "Browse" option in order to manually locate the directory where Microsoft Excel has been installed.
Sometimes problems with opening XLB files may not lie with the application itself, but can arise due to other causes, such as: