Some of the downloadable zip files for Developmental Math and Algebra 1-An Open Course are very large: 1.5 to 3 GB. After downloading, please compare your downloaded file size to the file you attempted to download. If there is a discrepancy, attempt the download again.
If you discover missing or corrupt files after unpacking a zip, you may have hit the file size "ceiling" on your Operating System during the unzipping process. On FAT32 file systems, the limit is 4GB. Some systems seem to balk at even smaller file sizes. You may wish to try downloading the file onto a computer with the NTFS file system. Or, if your use case warrants it, you may be able to download the course in smaller pieces, and reassemble them on your server or local system.