Quote:
Originally Posted by theducks
Your system (like mine) may become overly busy and that message appears. Among other things, look for HD activity LED flashing-mostly steady a indication the HD I/O has taken priority 
Possible causes:
1) low RAM (don't believe the minimums are enough. Think Ferengi)
2) Anti-virus is scanning way too much. Exclude your Calibre Library
3) Indexing service is trying to keep up with the changes (pant, pant  ) |
4) highly fragmented file system
5) Impending hard drive failure
I recently had an ailing drive. I had received a couple of drive & file related error messages and took them as a warning. I bought a replacement drive, installed it as a second drive and ran the drive manufacturer's recommended cloning software. During that time I continued to use the old aging drive. After I finally felt I had a reliable clone I removed to old drive and moved the new one into position as the primary.
Quite a number of file operations became much quicker. I hadn't realized how many performance issues were really the drive having to write, check, realize the write failed, rewrite, ... and finally get it right. Most OS's hide the occasional file system error and report an error only after a number of attempts fail. Calibre launches 3-5x faster, as do my other programs. File deletes, at the OS level and via apps like calibre, are also faster.
Keep in mind that calibre does not delete files itself. It simply asks the OS to do it. If the OS strains trying to delete the file, and possibly related folders, then calibre has to wait for it to finish before it can do any other file related operation.