You're here because you have a file that has a file extension ending in .gro. Files with the file extension .gro can only be launched by certain applications. It's possible that .gro files are data files rather than documents or media, which means they're not meant to be viewed at all.

A graphic object bitmap file is implemented with the same raster image compression specifications used for bitmap image files, and encoding standards proprietary to Hewlett-Packard are used for storing these graphic object bitmap files in the GRO format. These GRO files are used by particular models of scientific calculation and computation devices manufactured by Hewlett-Packard. These Hewlett-Packard scientific calculation and computation devices integrated with support for these GRO files include the HP-49 calculator and its predecessor, the HP-48 calculator. The firmware of these devices store digital visual objects and elements like charts and graphs in these GRO files. Users of computers running on Microsoft Windows-based systems can use HP callculator emulators to open and view the data stored in a GRO file. The XNView program is also another Microsoft Windows application that can be used to open files affixed with the .gro extension. These supported devices primarily use these GRO files to reference the data of the GRO file when a user makes changes to the numerical and scientific data associated to the graphs and charts stored in the corresponding GRO file.

Launch a .gro file, or any other file on your PC, by double-clicking it. If your file associations are set up correctly, the application that's meant to open your .gro file will open it. It's possible you may need to download or purchase the correct application. It's also possible that you have the correct application on your PC, but .gro files aren't yet associated with it. In this case, when you try to open a .gro file, you can tell Windows which application is the correct one for that file. From then on, opening a  .gro file will open the correct application. Click here to fix .gro file association errors

Be careful not to rename the extension on .gro files, or any other files. This will not change the file type. Only special conversion software can change a file from one file type to another.

A file extension is the set of three or four characters at the end of a filename; in this case, .gro. File extensions tell you what type of file it is, and tell Windows what programs can open it. Windows often associates a default program to each file extension, so that when you double-click the file, the program launches automatically. When that program is no longer on your PC, you can sometimes get an error when you try to open the associated file.