When you select this option, ThumbsPlus examines all files on the current drive looking for files that it recognizes and creates a thumbnail for each of them. If a thumbnail already exists for a file, its update date and time are checked against what is stored in the ThumbsPlus database. If the file has been modified since the thumbnail was made, it is regenerated from the file.
While running in single threaded mode, a progress box displays which indicates how much of the work is complete. This progress indicator is based on the total space in use on the drive, and is updated by the size of each file as it is examined. Since graphics files are usually grouped together, and different types of files take various amounts of time to analyze and reduce, this indicator does not really indicate the amount of progress made in time, but only how far through the disk ThumbsPlus has looked.
In multithreaded mode, no progress box is displayed. Instead, a new task entry is added to the tasks window. This entry displays the task name and the folder path that the task was started in. You can double click on the task entry for a running task and ThumbsPlus will select and display the folder that the task is currently working on.
In single threaded mode, you can click Cancel in the progress box to quit making thumbnails. This progress box also contains a list box where any errors which occur are listed. These errors include the file name being "nailed" at the time of the error. If any errors occur, the progress box will remain until you click OK.
In multithreaded mode, you can right click on the task displayed in the task window and select Quit Task to cancel the task. If any errors occur, the task entry will remain in the task window. You can double click on the task entry to review the errors that occurred.
Note: Most CD-ROM disks have useless "total size" information stored on them, so the progress percentage is essentially meaningless for these drives.