Shareware software is covered by copyright, as well. When you acquire software under a shareware arrangement, you are actually acquiring a license to use it, not own it. You acquire the license from the individual or company that owns the copyright. The conditions and restrictions of the license agreement vary from program to program and should be read carefully. The copyright holders for shareware allow purchasers to make and distribute copies of the software, but demand that if, after testing the software, you adopt it for use, you must pay for it. In general, shareware software licenses stipulate that (1) the software is covered by copyright, (2) although one archival copy of the software can be made, the backup copy cannot be used except when the original package fails or is destroyed, (3) modifications to the software are not allowed, (4) decompiling (i.e. reverse engineering) of the program code is not allowed without the permission of the copyright holder, and (5) development of new works built upon the package (derivative works) is not allowed without the permission of the copyright holder. Selling software as shareware is a marketing decision, it does not change the legal requirements with respect to copyright. That means that you can make a single archival copy, but you are obliged to pay for all copies adopted for use.