Source: Photoshop Support Knowledgebase
What’s covered: Issues when working from networks or removable media, recommended workflow, suggestions for troubleshooting.
When you save and open files across a network or from removable media, many variables affect application performance. Consequently, some problems (for example, damaged files, denied access, or slow performance) occur more frequently when you work across a network or from removable media than when you work from a local hard disk.
In these situations, Adobe Photoshop may return one of the following error messages:
– “Could not complete this operation because this file is in an unknown format.”
– “Could not complete the request because the file is locked.”
– “Could not save because of a disk error.”
– “This document has been damaged by disk error. The most likely cause of this error is a defective disk drive, SCSI, or SCSI termination. Pixels may be damaged. Open anyway?” (When you click OK, Photoshop may not open the file.)
Note: Problems using Photoshop files across a network or from removable media may be intermittent or delayed.
Adobe Technical Support only supports using Photoshop CS2 on a local hard disk because of the difficulty of re-creating or accurately identifying network- and peripheral-configuration problems. Adobe Technical Support does, however, support using Photoshop CS2 with Adobe Version Cue, a file version management feature in Adobe Creative Suite 2.0 that enables you to work with files in Version Cue workspaces on other computers. (See “Recommended workflow” below for more information about Version Cue.)
Issues when working from networks or removable media
Photoshop is a resource-intensive application, requiring more RAM and hard disk space than most other applications. While Photoshop will work across networks and removable media, these configurations compromise the performance and reliability of the application. For example, because Photoshop reads and writes image data while you work on an image, the faster the access speed of the disk containing your image or the Photoshop scratch disk files, the faster Photoshop can process image data. Internal hard disks have faster access speeds than network servers (a hard disk accessed over a network) and removable media.
Additional variables when using networks
There are many different types of network configurations (for example, multilaunch, client-server, or peer-peer) or types (for example, ethernet, token ring, or IP) made by many different companies. Each configuration requires specialized software and hardware, with varying set-ups, preferences, and updates. This additional layer of software and hardware increases the chances of an error occurring (for example, from line noise, RF interference, or packet collisions).
Multiple factors affect data transmission over a network, including file servers, routers, bridges, network cards, software, cables, connectors, power cables, and power supplies. Network connections can suddenly become unavailable, increasing the risk of data loss and application errors. During transmission and reception, network software verifies that data has been sent and received. The depth of verification depends on the network software package and may not be accessible by the operating system. When you try to save files across a network, you may receive the error, “Could not complete the request because the file is locked,” or “Could not save because of a disk error.” However, the network and operating system may not notify you if a Photoshop image or scratch disk file contains damaged or incomplete information.
Additional variables when using removable media
There are many kinds of removable media (for example, external parallel [Windows], external/internal SCSI, internal IDE) manufactured by many companies. They all require cables and device drivers to be recognized by your operating system. Also, removable media are more easily damaged than internal disks, increasing the risk of damaged image data or scratch disk files.
If you use Photoshop CS2 with Adobe Creative Suite 2.0, you can work with files in Version Cue. This file version management feature in Adobe Creative Suite makes files available to everyone in your work group or team from a single workspace. You don’t have to leave Photoshop CS2 to work with files in a Version Cue workspace — you can preview files, search for files based on metadata, such as author name, keyword, or version comments, and set permissions from within Photoshop. For more information, visit the Adobe Web site at www.adobe.com/products/creativesuite/main.html or refer to Adobe Creative Suite documentation.
If you use Photoshop CS2 without Adobe Creative Suite, Adobe Technical Support strongly recommends working in Photoshop directly on the local hard disk to prevent data loss. Save files to your hard disk first and then transfer them to the network or removable drive in the Finder or in Windows Explorer. To retrieve files, copy them in the Finder or in Windows Explorer from the network or removable drive to your hard disk. You can then open the files in Photoshop. This workflow also avoids problems that occur when network system setups (for example, Windows NT Server, Netware, or AppleTalk) or removable media device drivers are not completely compatible with the operating system or with Photoshop.
Suggestions for troubleshooting
Different factors can cause problems with application performance, including memory conflicts among device drivers, damaged or conflicting files, operating system software, hardware or low-level DOS (Windows) problems. If you work directly from networks or from removable media and you experience problems, use the suggestions below to troubleshoot.
Disclaimer: The following instructions are provided as a courtesy. Adobe Systems does not provide support for networks and removable media.
– Make sure that you are using the latest version of Photoshop. Free Photoshop updates are available from the Adobe website at www.adobe.com/support/downloads/.
– Transfer the file from the network or removable disk to a local hard disk, and then open it in Photoshop.
Note: Once a file has artifacts, they may be permanently a part of the image data. Replicate your image in a new file using the local hard disk.
– Use another computer connected to the same network or type of removable media.
– Set the scratch disks to a local hard disk.
– Check with your network administrator about known issues with the network or changes in network configuration (for example, updated drivers or changed access privileges).
– Make sure that Photoshop is installed on and running from a local hard disk, and try to replicate the problem. If you can, troubleshoot the problem on the local configuration. If you can’t, your problem may be caused by working from removable media or a network.