Sending documents as e-mail attachments can be incredibly helpful when you’re collaborating, when you don’t have time to leave your desk, or when you need to get a document to a distant colleague in a hurry. But there are guidelines you should consider if you wish to use attachments effectively without creating more inconveniences than you are avoiding by using them. Consider the following potential problems:

Before attaching a file, consider how much disk space the file consumes (in Windows, you can determine the size of a file by right-clicking on it and selecting "Properties." In Mac OS, you can determine size by clicking once on the file in the Finder). Files of less than one megabyte are generally fine to use, but if the file you wish to send is larger than one megabyte, it may slow transmission speed—particularly if your recipient is using a dial-up connection—and possibly result in file refusal; some e-mail providers and e-mail software will not accept large files.

Computer viruses are often transmitted through e-mail attachments; many, in fact, rely exclusively on e-mail software. As a result, many recipients have become very cautious—and rightly so—about opening e-mail attachments. In addition, many organizations have installed network firewalls that automatically scan and refuse unknown attachment types.

If you receive attachments you don’t recognize or expect, or if you receive attachments from unknown senders, do not open them without first conducting a virus scan. And the first time you send an attachment to a new recipient, be sure to verify that they have received your attachment and were able to open it.

Despite the difficulties with file size and viruses, attachments are increasingly becoming standard practice in many organizations. But before you send a document as an attachment, ensure that an attachment is the best way to achieve your desired purpose. Attachments are best when it’s important that original formatting be preserved, or when the data can only be displayed in a specific software package. But too often, attachments are used in situations when pasting text into a message would save file size, eliminate virus dangers, and eliminate compatibility issues (for example, one user is using WordPerfect for Windows and another is using Word for Mac).